Re: [time-nuts] CS reservoir depletion
Having two HP CBT's minus enclosure sitting on my window sill, allow me to ad my two cents worth. Looking at the assemblies I see more art than science and duplicating something like that would most likely end in failure. Comparing that to the previous H Maser discussions the collective know how and resources of the list could maybe result in a Maser. As to refurbishing tubes some of us have discussed that off line and in my opinion with proper tools and equipment cleaning and replacing cesium is doable. Cynics say the manufacturers of tubes could do it but rather sell only new ones since they are the only source of the much more expensive new tube. I think that is only half the story. The reason in my opinion why refurbishing the tube is commercially not viable is you have to ask: when done what do you really have? You have not eliminated some of the failure modes, in the case of the 5071 the data in the EPROM does not necessarily reflect the tube and who could say how long the tube would last? A crap shoot. I have a HP 5061 B and a HP 5062 C but eventually want to replace them totally with a Tbolt-Rb-HP 10811 combination using two digital loops that are tailored to the devices. I am now focusing on the thermal management in order to get maximum performance. There is work going on by some members of the list to develop more sophisticated digital loops. Lets face it, with GPS properly used, having a Cesium Standard will give you the warm feeling that you have a primary standard. By the way that is why I repeatedly have asked the list if there is any long term Tbolt data out there comparing the 1 PPS or the 10 MHz with a Maser. I hope this is worth two cents. Bert Kehren ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
On 01/15/2011 11:20 AM, Jean-Louis Noel wrote: Hi Robert, From: Robert Vassar rvas...@rob-vassar.com You could probably safely handle a small quantity of Rb in a home lab environment for a short period of time. Pure Cesium would be a significant risk. As you can see on page 28 vials remains untouched till everythings are in place and else broken. http://jila01.colorado.edu/pubs/thesis/bennett/ch3.pdf For a vial of cesium check ebay 280612515679 No, do read at page 27 first. There is some handling in a glove-box filled with argon and movement from that one before final assembly etc. Doable, but not quite the same thing as you described. There is patents for CBT solutions where the ampule is broken when placed in the CBT, complete with metal cages to handle the ballistics of glass splinters. Doing it once is one thing. Doing it several times is another. A home-made tube is bound to have an experimental touch to it. So the caesium oven needs to be isolated when experimenter tinkers around. In comparison a rubidium setup seems much safer as it is sealed up in its glass-ware for the rest of the device life unless you are very clumsy. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Hi Magnus, From: Magnus Danielson mag...@rubidium.dyndns.org As you can see on page 28 vials remains untouched till everythings are in place and else broken. No, do read at page 27 first. There is some handling in a glove-box filled with argon and movement from that one before final assembly etc. Yes, but I think you can find a solution to break the vials when everything is in place. Safer! Bye, Jean-Louis ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
On 01/16/2011 04:38 PM, Jean-Louis Noel wrote: Hi Magnus, From: Magnus Danielson mag...@rubidium.dyndns.org As you can see on page 28 vials remains untouched till everythings are in place and else broken. No, do read at page 27 first. There is some handling in a glove-box filled with argon and movement from that one before final assembly etc. Yes, but I think you can find a solution to break the vials when everything is in place. Safer! You can, but that description was not the best inspiration. I'll have to dig my archive to find a better example. But honestly, this would only be one tiny details out of many. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
The vials are commonly broken in vaccuo with a magnet and steel plunger. -John === Hi Magnus, From: Magnus Danielson mag...@rubidium.dyndns.org As you can see on page 28 vials remains untouched till everythings are in place and else broken. No, do read at page 27 first. There is some handling in a glove-box filled with argon and movement from that one before final assembly etc. Yes, but I think you can find a solution to break the vials when everything is in place. Safer! Bye, Jean-Louis ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
What interested me was the beam collimator. I'd thought the beam would be collimated and small diameter like a LASER, but the setup clearly is to produve a beam of Cs maybe 1 to 1.5 inches in diameter. -John = On 01/16/2011 04:38 PM, Jean-Louis Noel wrote: Hi Magnus, From: Magnus Danielson mag...@rubidium.dyndns.org As you can see on page 28 vials remains untouched till everythings are in place and else broken. No, do read at page 27 first. There is some handling in a glove-box filled with argon and movement from that one before final assembly etc. Yes, but I think you can find a solution to break the vials when everything is in place. Safer! You can, but that description was not the best inspiration. I'll have to dig my archive to find a better example. But honestly, this would only be one tiny details out of many. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
By the way that is why I repeatedly have asked the list if there is any long term Tbolt data out there comparing the 1 PPS or the 10 MHz with a Maser. I hope this is worth two cents. Bert Kehren Bert, Here's a 4+ day run between a TBolt 10 MHz and maser. Phase samples are 1 Hz, units are seconds. The arbitrary frequency and phase offset have been removed. http://www.leapsecond.com/pages/tbolt/log36116.dat.gz ADEV(tau): 1 1.3349e-012 10 4.8781e-012 100 8.8310e-012 1000 2.9840e-012 1 4.0155e-013 86400 4.8494e-014 10 3.9650e-014 If you need more info let me know. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Thank you. Bert Kehren In a message dated 1/16/2011 12:03:53 P.M. Eastern Standard Time, hol...@hotmail.com writes: Baring any holdover events, the long term output of a properly configured tbolt should exceed any single cesium source or maser. If you assume the 1 PPS signal is always accurate to 5 ns that is an error of 1 part in 1.6E16 at tau=1 year. Also, there is code in Lady Heather that implements an external disciplining loop that outperforms the one in the tbolt firmware. - By the way that is why I repeatedly have asked the list if there is any long term Tbolt data out there comparing the 1 PPS or the 10 MHz with a Maser. I hope this is worth two cents. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Hi While I agree with the idea of a super GPS as being a good standard, there are some reasons for needing something else: 1) You need something to compare *your* GPS gizmo to in your setting. Knowing that it might be working ok is not as good as knowing that it is working ok. 2) Without some fancy corrections, GPS can indeed drift. The period might be hours, it could be days. The net effects will cancel over a long enough time, but that time may be longer than your loop can suppress. 3) Anything that creates a fast change in your local fly wheel standards will still show up on the output. It will walk out with time. Things in this category are stuff like a step change in the supply voltage creating a change in your OCXO output. All of that can be worked on. Much of it applies equally to having a single Cs in the basement. There are a couple of things the GPS gives you that the Cs will not: 1) It will tell you what time it is to within a few ns. Most of us frequency guys don't realize quite how hard that is to do without GPS. 2) The long term stability (because it's steered) of the GPS is going to eventually beat anything else out there. If you do really long data runs (months, years) the GPS will always win. 3) Low cost to run. Even if you have a working Cs, how long until the tube goes? The GPS has essentially no wear out mechanisms. The Cs is full of strange stuff. The parts in the GPS are pretty cheap / easy to find. 4) Easy to duplicate. Everything you are likely to use in a fancy GPS setup is commonly available in quantity. The components are known good and cheap. No gamble on a tube or other hard to replace stuff. 5) Easy to run. There's not much mystery about what's going on. Nothing is hidden in a vacuum bottle. No hidden numbers in a rom. Everything is pretty much right in front of you. The only exception would be the disciplining software in the GPSDO if you choose to use it. I admit that the GPS makes a *lot* of sense. I sure wouldn't turn down a nice shinny new HP cesium if one showed up on my doorstep. Bob On Jan 16, 2011, at 7:01 AM, ewkeh...@aol.com wrote: Having two HP CBT's minus enclosure sitting on my window sill, allow me to ad my two cents worth. Looking at the assemblies I see more art than science and duplicating something like that would most likely end in failure. Comparing that to the previous H Maser discussions the collective know how and resources of the list could maybe result in a Maser. As to refurbishing tubes some of us have discussed that off line and in my opinion with proper tools and equipment cleaning and replacing cesium is doable. Cynics say the manufacturers of tubes could do it but rather sell only new ones since they are the only source of the much more expensive new tube. I think that is only half the story. The reason in my opinion why refurbishing the tube is commercially not viable is you have to ask: when done what do you really have? You have not eliminated some of the failure modes, in the case of the 5071 the data in the EPROM does not necessarily reflect the tube and who could say how long the tube would last? A crap shoot. I have a HP 5061 B and a HP 5062 C but eventually want to replace them totally with a Tbolt-Rb-HP 10811 combination using two digital loops that are tailored to the devices. I am now focusing on the thermal management in order to get maximum performance. There is work going on by some members of the list to develop more sophisticated digital loops. Lets face it, with GPS properly used, having a Cesium Standard will give you the warm feeling that you have a primary standard. By the way that is why I repeatedly have asked the list if there is any long term Tbolt data out there comparing the 1 PPS or the 10 MHz with a Maser. I hope this is worth two cents. Bert Kehren ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
1 OR 1.5 INCHES IS ONLY ONE OF THE DIMENSIONS. THE OTHER ONE IS SMALLER, AND THE BEAM IS NOT CIRCULAR ( OR NOT CONICAL). At 17:44 16.1.2011, you wrote: What interested me was the beam collimator. I'd thought the beam would be collimated and small diameter like a LASER, but the setup clearly is to produve a beam of Cs maybe 1 to 1.5 inches in diameter. -John = On 01/16/2011 04:38 PM, Jean-Louis Noel wrote: Hi Magnus, From: Magnus Danielson mag...@rubidium.dyndns.org As you can see on page 28 vials remains untouched till everythings are in place and else broken. No, do read at page 27 first. There is some handling in a glove-box filled with argon and movement from that one before final assembly etc. Yes, but I think you can find a solution to break the vials when everything is in place. Safer! You can, but that description was not the best inspiration. I'll have to dig my archive to find a better example. But honestly, this would only be one tiny details out of many. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Hi Robert, From: Robert Vassar rvas...@rob-vassar.com You could probably safely handle a small quantity of Rb in a home lab environment for a short period of time. Pure Cesium would be a significant risk. As you can see on page 28 vials remains untouched till everythings are in place and else broken. http://jila01.colorado.edu/pubs/thesis/bennett/ch3.pdf For a vial of cesium check ebay 280612515679 Bye, Jean-Louis ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Tom That is one thing I noticed even without the CS the system is very stable with the Xtal. My comment was tagging on to a previous one and I couldn't resist the fact that I get might old stuff. Good comment on the standard. Indeed I run my 5065 every month or so for a day or two insuring its stable and no problems have or are cropping up. My 5061 came from the Naval observatory. I just know the next hamfest or MIT flea I will find a new tube for it for $10 or 20. Not to likely. Regards On Fri, Jan 14, 2011 at 1:01 AM, Tom Van Baak t...@leapsecond.com wrote: Hi Tom been quite a while hope you are well. The never run out comments, not from me. Look at the previous thread I tagged onto. My humor is that most of the CS tubes we get are very long in the tooth usually way past whatever anyone would say they are good for. That is so true. It always amazes to pick up a 30 year old 5061A and find that it still works. Sometimes the reason is that it is already on its 2nd or 3rd replacement tube before it went to surplus. In which case you're happy for years. Other times it may be that the 5061A was used only very intermittently and the tube is the low S/N original. A real gem would be one that was kept in cs-off mode except for a few hours once a month to keep the OCXO within some loose cal lab spec. Even after decades it would be as good as new. For many frequency applications there is no reason to run in full cs-locked mode. This is also true if you need good short-term stability. The free-running OCXO in most Cs (and GPSDO for that matter) are more stable short-term when the loop is open. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Before this indelible conversation goes too far, note that cesium beam frequency standards are explicitly included on the U.S. ITAR list under §121.IV.28 and that, under §120.10.a, this prohibits the dissemination of (1) Information, other than software as defined in § 120.10(d), which is required for the design development, production, manufacture, assembly, operation, repair, testing, maintenance or modification of defense articles. This includes information in the form of blueprints, drawings, photographs, plans, instructions and documentation. -- -RL ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Hi, I can get a 00105-6013 xtal oscillator that is the type used in the 5051A and 5065 standards. Does it worth for a standalone frequency standard or the more modern compact types such the miniature units from the telco towers salvage coming from China are more convenient? I realize that I need to provide both with a low noise power supply, specially for the frequency control voltage, but the in modern ones the supply issue is simpler and they give the (usually) more convenient 10 MHz output instead of 5 MHz. I don't know if the HP unit is usually quieter or more stable. I also I know that it depends of the intended use. In this case it is for my home lab which includes a compact Rb and a soon to be built GPSDO. Regards, Ignacio, EB4APL El 14/01/2011 7:01, Tom Van Baak wrote: Hi Tom been quite a while hope you are well. The never run out comments, not from me. Look at the previous thread I tagged onto. My humor is that most of the CS tubes we get are very long in the tooth usually way past whatever anyone would say they are good for. That is so true. It always amazes to pick up a 30 year old 5061A and find that it still works. Sometimes the reason is that it is already on its 2nd or 3rd replacement tube before it went to surplus. In which case you're happy for years. Other times it may be that the 5061A was used only very intermittently and the tube is the low S/N original. A real gem would be one that was kept in cs-off mode except for a few hours once a month to keep the OCXO within some loose cal lab spec. Even after decades it would be as good as new. For many frequency applications there is no reason to run in full cs-locked mode. This is also true if you need good short-term stability. The free-running OCXO in most Cs (and GPSDO for that matter) are more stable short-term when the loop is open. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
In your dreams. There was a very nice HP Cs there a few years ago, but it had a properety tag that I recognized. I knew that unit had a known bad Cs tube, as I seen it at a company surplus sale a month before, but that didn't stop the guy hawking it as working for well over $5K. Caveat Emptor!! -John == Tom That is one thing I noticed even without the CS the system is very stable with the Xtal. My comment was tagging on to a previous one and I couldn't resist the fact that I get might old stuff. Good comment on the standard. Indeed I run my 5065 every month or so for a day or two insuring its stable and no problems have or are cropping up. My 5061 came from the Naval observatory. I just know the next hamfest or MIT flea I will find a new tube for it for $10 or 20. Not to likely. Regards On Fri, Jan 14, 2011 at 1:01 AM, Tom Van Baak t...@leapsecond.com wrote: Hi Tom been quite a while hope you are well. The never run out comments, not from me. Look at the previous thread I tagged onto. My humor is that most of the CS tubes we get are very long in the tooth usually way past whatever anyone would say they are good for. That is so true. It always amazes to pick up a 30 year old 5061A and find that it still works. Sometimes the reason is that it is already on its 2nd or 3rd replacement tube before it went to surplus. In which case you're happy for years. Other times it may be that the 5061A was used only very intermittently and the tube is the low S/N original. A real gem would be one that was kept in cs-off mode except for a few hours once a month to keep the OCXO within some loose cal lab spec. Even after decades it would be as good as new. For many frequency applications there is no reason to run in full cs-locked mode. This is also true if you need good short-term stability. The free-running OCXO in most Cs (and GPSDO for that matter) are more stable short-term when the loop is open. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Hi, From: Robert Lutwak rlut...@gmail.com Before this indelible conversation goes too far, note that cesium beam frequency standards are explicitly included on the U.S. ITAR list under §121.IV.28 and that, under §120.10.a, this prohibits the dissemination of :-) http://hal.archives-ouvertes.fr/docs/00/22/17/25/PDF/ajp-jphyscol198142C830.pdf Bye, Jean-Louis ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Hi The 105 oscillator is a nice OCXO. I certainly would not throw one away. There are indeed better parts out there. It all depends on what you are trying to do. The phase noise of the unit is not as good as some of the 10 MHz stuff. I would not base a microwave synthesizer on one. It's short term stability is a depends on the one you have. Testing would be needed here. Aging wise it should be pretty good. That assumes it was on power for a good part of it's life. If it's been on the shelf for 20 years, you may need to run it for a while ... Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of EB4APL Sent: Friday, January 14, 2011 10:05 AM To: time-nuts@febo.com Subject: Re: [time-nuts] CS reservoir depletion Hi, I can get a 00105-6013 xtal oscillator that is the type used in the 5051A and 5065 standards. Does it worth for a standalone frequency standard or the more modern compact types such the miniature units from the telco towers salvage coming from China are more convenient? I realize that I need to provide both with a low noise power supply, specially for the frequency control voltage, but the in modern ones the supply issue is simpler and they give the (usually) more convenient 10 MHz output instead of 5 MHz. I don't know if the HP unit is usually quieter or more stable. I also I know that it depends of the intended use. In this case it is for my home lab which includes a compact Rb and a soon to be built GPSDO. Regards, Ignacio, EB4APL El 14/01/2011 7:01, Tom Van Baak wrote: Hi Tom been quite a while hope you are well. The never run out comments, not from me. Look at the previous thread I tagged onto. My humor is that most of the CS tubes we get are very long in the tooth usually way past whatever anyone would say they are good for. That is so true. It always amazes to pick up a 30 year old 5061A and find that it still works. Sometimes the reason is that it is already on its 2nd or 3rd replacement tube before it went to surplus. In which case you're happy for years. Other times it may be that the 5061A was used only very intermittently and the tube is the low S/N original. A real gem would be one that was kept in cs-off mode except for a few hours once a month to keep the OCXO within some loose cal lab spec. Even after decades it would be as good as new. For many frequency applications there is no reason to run in full cs-locked mode. This is also true if you need good short-term stability. The free-running OCXO in most Cs (and GPSDO for that matter) are more stable short-term when the loop is open. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Hi Through the flips and flops of HP = Agilent = Symmetricom various products have changed badges and locations. They appear to be consolidating cesium standard production at the old FTS plant in Beverly(?) MA. Ultimately I suspect they will redesign the product line to rationalize it. That should be fun to watch. It would be much less fun to be caught in the middle of. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Jeffrey Okamitsu Sent: Friday, January 14, 2011 9:18 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] CS reservoir depletion ...We're still waiting to see if they can figure out how make 5071 CBT's on the east coast, let alone someone's garage Rick...what did you mean by on the east coast? Just curious. 73, Jeff W3KL Jeffrey K. Okamitsu, PhD, MBA +1-609-638-5402 US Mobile Phone +1-240-421-0692 GSM Mobile Phone From: Richard (Rick) Karlquist rich...@karlquist.com To: scmcgr...@gmail.com; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thu, January 13, 2011 12:09:01 AM Subject: Re: [time-nuts] CS reservoir depletion This is a popular FAQ that Cs engineers hear. The correct answer (at least for HP/Agilent CBTs) is that there is plenty of Cs in the tube, and they don't fail because they ran out of Cs. Something else will always wear out first. Regarding the general idea of rebuilding CBT's: a used CBT is so cesiated that it is not practical to rebuild it even on the regular CBT line. Even if it were, it is unlikely a time nut would have the necessary high vacuum equipment. It is pretty serious stuff. You also need to be able to laser weld the case together when you are finished. Sure seems like a don't try this at home thing. We're still waiting to see if they can figure out how make 5071 CBT's on the east coast, let alone someone's garage. Rick Karlquist N6RK On 1/11/2011 4:06 PM, scmcgr...@gmail.com wrote: Now that we are discussing how to restore Rb lamps. Has anyone given any thought to refilling or refluxing the Cs in depleted Cs tubes? Obviously opening would require high vaccum equipment - which is a totally separate category of nut (Or is it?) Scott Scott Sent from my Verizon Wireless BlackBerry ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Hi I suspect you are a lot more likely to come up with a new tube by talking to Bert before he gets rid of his inventory Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of paul swed Sent: Friday, January 14, 2011 9:10 AM To: Tom Van Baak; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] CS reservoir depletion Tom That is one thing I noticed even without the CS the system is very stable with the Xtal. My comment was tagging on to a previous one and I couldn't resist the fact that I get might old stuff. Good comment on the standard. Indeed I run my 5065 every month or so for a day or two insuring its stable and no problems have or are cropping up. My 5061 came from the Naval observatory. I just know the next hamfest or MIT flea I will find a new tube for it for $10 or 20. Not to likely. Regards On Fri, Jan 14, 2011 at 1:01 AM, Tom Van Baak t...@leapsecond.com wrote: Hi Tom been quite a while hope you are well. The never run out comments, not from me. Look at the previous thread I tagged onto. My humor is that most of the CS tubes we get are very long in the tooth usually way past whatever anyone would say they are good for. That is so true. It always amazes to pick up a 30 year old 5061A and find that it still works. Sometimes the reason is that it is already on its 2nd or 3rd replacement tube before it went to surplus. In which case you're happy for years. Other times it may be that the 5061A was used only very intermittently and the tube is the low S/N original. A real gem would be one that was kept in cs-off mode except for a few hours once a month to keep the OCXO within some loose cal lab spec. Even after decades it would be as good as new. For many frequency applications there is no reason to run in full cs-locked mode. This is also true if you need good short-term stability. The free-running OCXO in most Cs (and GPSDO for that matter) are more stable short-term when the loop is open. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Hi I've seen some 10811's in GPSDO's that take many weeks to settle below 3.0 x 10^-10 per day. It's rare to see one that's been on power recently behave that way. The ones I'm looking at have been off power for years and stored in an outdoor shed (no heat / cooling / humidity control). Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Rick Karlquist Sent: Friday, January 14, 2011 1:34 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] CS reservoir depletion Bob Camp wrote: Hi There is a lot of data that says crystals relax while off power. The older they are (the older the process) the more likely they are to do so. The net effect is that they will move much faster on a per day basis than you would expect them to. They will eventually calm down, but it can take months. My experience with 10811's is that it didn't matter much whether they have been off for a week or a year as far as settling down was concerned. Also on and off effectively refers to the oven. Turning the oscillator on and off while keeping the oven on continuously has little effect. Rick Karlquist N6RK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
On 1/14/11 6:55 AM, Robert Lutwak wrote: Before this indelible conversation goes too far, note that cesium beam frequency standards are explicitly included on the U.S. ITAR list under §121.IV.28 and that, under §120.10.a, this prohibits the dissemination of (1) Information, other than software as defined in § 120.10(d), which is required for the design development, production, manufacture, assembly, operation, repair, testing, maintenance or modification of defense articles. This includes information in the form of blueprints, drawings, photographs, plans, instructions and documentation. http://www.pmddtc.state.gov/regulations_laws/itar_official.html I don't think so.. I looked through the current USML, and the word cesium doesn't appear in it. Spaceflight qualified atomic frequency standards ARE on the USML, but I didn't see anything in there about standards for terrestrial use. Might have missed it, or maybe it's a dual use and controlled under the EAR, not ITAR? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
On 1/14/11 8:12 AM, Jean-Louis Noel wrote: Hi, From: Robert Lutwak rlut...@gmail.com Before this indelible conversation goes too far, note that cesium beam frequency standards are explicitly included on the U.S. ITAR list under §121.IV.28 and that, under §120.10.a, this prohibits the dissemination of :-) http://hal.archives-ouvertes.fr/docs/00/22/17/25/PDF/ajp-jphyscol198142C830.pdf Sadly, it has been made abundantly clear to me and my colleagues that merely because something is published in the open literature does not make it export-control free. We are specifically cautioned that pointing someone to a set of papers in a particular area falls in the category of providing technical assistance with the design of defense articles, for which an export license is needed. If you come at it with very clean hands.. purely research into fundamental scientific principles.. then you are pretty safe, but as soon as you start talking about design and build specifics, or identifying and ranking alternatives, then you're in dangerous territory. (speaking here ONLY of things that go into space, since unless specifically exempted, pretty much anything in space is a defense article) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
In message 4d30be89.8050...@earthlink.net, jimlux writes: On 1/14/11 8:12 AM, Jean-Louis Noel wrote: Sadly, it has been made abundantly clear to me and my colleagues that merely because something is published in the open literature does not make it export-control free. We are specifically cautioned that pointing someone to a set of papers in a particular area falls in the category of providing technical assistance with the design of defense articles, for which an export license is needed. The depressing thing is that is almost word for word what a russian atomic physicist said in 1989 at the Global Issues for an Open World conference here in Copenhagen. Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Hi Well that crosses off any discussion of Tang as a breakfast drink (You would indeed need to be fairly old to remember the TV commercials selling it based on it's space connection). Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of jimlux Sent: Friday, January 14, 2011 4:22 PM To: time-nuts@febo.com Subject: Re: [time-nuts] CS reservoir depletion On 1/14/11 8:12 AM, Jean-Louis Noel wrote: Hi, From: Robert Lutwak rlut...@gmail.com Before this indelible conversation goes too far, note that cesium beam frequency standards are explicitly included on the U.S. ITAR list under §121.IV.28 and that, under §120.10.a, this prohibits the dissemination of :-) http://hal.archives-ouvertes.fr/docs/00/22/17/25/PDF/ajp-jphyscol198142C830. pdf Sadly, it has been made abundantly clear to me and my colleagues that merely because something is published in the open literature does not make it export-control free. We are specifically cautioned that pointing someone to a set of papers in a particular area falls in the category of providing technical assistance with the design of defense articles, for which an export license is needed. If you come at it with very clean hands.. purely research into fundamental scientific principles.. then you are pretty safe, but as soon as you start talking about design and build specifics, or identifying and ranking alternatives, then you're in dangerous territory. (speaking here ONLY of things that go into space, since unless specifically exempted, pretty much anything in space is a defense article) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Hi Not to mention some conversations to the effect that indeed ITAR did force the Russians to develop their own Space qualified Cs standards. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Poul-Henning Kamp Sent: Friday, January 14, 2011 4:36 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] CS reservoir depletion In message 4d30be89.8050...@earthlink.net, jimlux writes: On 1/14/11 8:12 AM, Jean-Louis Noel wrote: Sadly, it has been made abundantly clear to me and my colleagues that merely because something is published in the open literature does not make it export-control free. We are specifically cautioned that pointing someone to a set of papers in a particular area falls in the category of providing technical assistance with the design of defense articles, for which an export license is needed. The depressing thing is that is almost word for word what a russian atomic physicist said in 1989 at the Global Issues for an Open World conference here in Copenhagen. Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Hi, From: jimlux jim...@earthlink.net pretty much anything in space is a defense article) I can't imagine they could have done such mistake! http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2doc=GetTRDoc.pdfAD=ADA509345 (second page) http://tycho.usno.navy.mil/ptti/ptti2001/paper2.pdf Bye, Jean-Louis ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Thank you Bob, I think I'll get it, just to have another quality oscillator. About its aging I think it is new, probably a spare unit. since there are not signs of any solder on the pins. Best regards, Ignacio El 14/01/2011 18:11, Bob Camp escribió: Hi The 105 oscillator is a nice OCXO. I certainly would not throw one away. There are indeed better parts out there. It all depends on what you are trying to do. The phase noise of the unit is not as good as some of the 10 MHz stuff. I would not base a microwave synthesizer on one. It's short term stability is a depends on the one you have. Testing would be needed here. Aging wise it should be pretty good. That assumes it was on power for a good part of it's life. If it's been on the shelf for 20 years, you may need to run it for a while ... Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of EB4APL Sent: Friday, January 14, 2011 10:05 AM To: time-nuts@febo.com Subject: Re: [time-nuts] CS reservoir depletion Hi, I can get a 00105-6013 xtal oscillator that is the type used in the 5051A and 5065 standards. Does it worth for a standalone frequency standard or the more modern compact types such the miniature units from the telco towers salvage coming from China are more convenient? I realize that I need to provide both with a low noise power supply, specially for the frequency control voltage, but the in modern ones the supply issue is simpler and they give the (usually) more convenient 10 MHz output instead of 5 MHz. I don't know if the HP unit is usually quieter or more stable. I also I know that it depends of the intended use. In this case it is for my home lab which includes a compact Rb and a soon to be built GPSDO. Regards, Ignacio, EB4APL El 14/01/2011 7:01, Tom Van Baak wrote: Hi Tom been quite a while hope you are well. The never run out comments, not from me. Look at the previous thread I tagged onto. My humor is that most of the CS tubes we get are very long in the tooth usually way past whatever anyone would say they are good for. That is so true. It always amazes to pick up a 30 year old 5061A and find that it still works. Sometimes the reason is that it is already on its 2nd or 3rd replacement tube before it went to surplus. In which case you're happy for years. Other times it may be that the 5061A was used only very intermittently and the tube is the low S/N original. A real gem would be one that was kept in cs-off mode except for a few hours once a month to keep the OCXO within some loose cal lab spec. Even after decades it would be as good as new. For many frequency applications there is no reason to run in full cs-locked mode. This is also true if you need good short-term stability. The free-running OCXO in most Cs (and GPSDO for that matter) are more stable short-term when the loop is open. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
On Jan 14, 2011, at 1:45 PM, Bob Camp li...@rtty.us wrote: Hi Well that crosses off any discussion of Tang as a breakfast drink (You would indeed need to be fairly old to remember the TV commercials selling it based on it's space connection). Bob Tang is a good example of a dual use technology(?). No ITAR worries, just dept of commerce. Unless you had some scheme for turning it into a weapon A prospect that is frightening to contemplate. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Tang was a WMD (Weapon of Massive Disgust) in and of itself. -John On Jan 14, 2011, at 1:45 PM, Bob Camp li...@rtty.us wrote: Hi Well that crosses off any discussion of Tang as a breakfast drink (You would indeed need to be fairly old to remember the TV commercials selling it based on it's space connection). Bob Tang is a good example of a dual use technology(?). No ITAR worries, just dept of commerce. Unless you had some scheme for turning it into a weapon A prospect that is frightening to contemplate. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
On Jan 13, 2011, at 5:18 PM, Rick Karlquist wrote: The other problem for the garage builder is that one of the Rb isotopes is slightly radioactive. Probably not OK to have in your garage. I used to perform Rb/Sr geochronology wet bench chemistry in college. Rb-87 has a half-life on the order of ~48.8 billion years. Several multiples of the estimated age of the universe. The potassium-40 in your own body is a much greater threat, followed by C-14, and various natural sources, smoke detectors, camping lantern mantles, etc... I understand the average person has several thousand K40 decay events in their body per second. Handling pure Rb is another thing entirely. It is quite moisture sensitive / pyrophoric, and tends to form shock sensitive peroxides even when submerged under oil. You really need to store the stuff in a vacuum, or under an inert atmosphere. But since we're also discussing Cesium, I should point out that it is actually far worse in this regard. You could probably safely handle a small quantity of Rb in a home lab environment for a short period of time. Pure Cesium would be a significant risk. Rob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
I used to perform Rb/Sr geochronology wet bench chemistry in college. Rb-87 has a half-life on the order of ~48.8 billion years. Several multiples of the estimated age of the universe. The potassium-40 in your own body is a much greater threat, followed by C-14, and various natural sources, smoke detectors, camping lantern mantles, etc... I understand the average person has several thousand K40 decay events in their body per second. I don't know the number od K-40 decays per second, but it's certainly non-trivial. Asw a freshman science project, I went into a chamber made out of pre-atomic age battleship armor plate and had the K eminations counted with a scintillator and MCA. From that measurement, we were able to determine my lean body mass. Handling pure Rb is another thing entirely. It is quite moisture sensitive / pyrophoric, and tends to form shock sensitive peroxides even when submerged under oil. You really need to store the stuff in a vacuum, or under an inert atmosphere. But since we're also discussing Cesium, I should point out that it is actually far worse in this regard. You could probably safely handle a small quantity of Rb in a home lab environment for a short period of time. Pure Cesium would be a significant risk. Rob I think any pure alkali metal basically has to be handled in a good vacuum and moved around by distillation. It's easy enough as you are concerned with grams, at most, not pounds of the stuff. -John == ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
I think any pure alkali metal basically has to be handled in a good vacuum and moved around by distillation. It's easy enough as you are concerned with grams, at most, not pounds of the stuff. -John You obviously didn't see the Myth Busters episode where they used several pounds of sodium to bust a bathtub. Joe Gray W5JG ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
It may not be necessary to open a tube to renew the supply of an alkali metal. I remember an experiment where an incandescent light bulb was dipped into molten sodium chloride in an iron vessel. The filament was run and a voltage between the filament and the iron vessel caused sodium ions to migrate through the glass into the bulb. Sodium accumulated in the bulb. It is obviously a slow process, but then you did not need to put much Cs in the bulb. Why not use it to recharge an alkali metal lamp? cheers, Neville Michie On 12/01/2011, at 11:06 AM, scmcgr...@gmail.com wrote: Now that we are discussing how to restore Rb lamps. Has anyone given any thought to refilling or refluxing the Cs in depleted Cs tubes? Obviously opening would require high vaccum equipment - which is a totally separate category of nut (Or is it?) Scott Scott Sent from my Verizon Wireless BlackBerry ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/ time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
I suppose that would be possible if a C beam standard worked like a rubidium reference, but alas, they are different in virtually all respects. Think of the C beam as having a small kettle full of cesium that is put on a low simmer. The kettle keeps the cesium molten, and bubbling up minute amounts of cesium vapor. How are you going to refill the kettle when it lives in the middle of a hard vacuum chamber? The best you could do with your technique (assuming it is even possible) is to coat the walls of the vacuum chamber with cesium... Kind of like trying to fill the gas tank by hosing the car down with gasoline. Besides, if HP can be believed, the kettle never runs out of cesium before the receiving end of the tube gets completely choked on waste cesium metal. That waste cesium needs to be removed, and the electron multiplier needs to be restored, at a minimum and the ion pump is probably full up too. -Chuck Harris Neville Michie wrote: It may not be necessary to open a tube to renew the supply of an alkali metal. I remember an experiment where an incandescent light bulb was dipped into molten sodium chloride in an iron vessel. The filament was run and a voltage between the filament and the iron vessel caused sodium ions to migrate through the glass into the bulb. Sodium accumulated in the bulb. It is obviously a slow process, but then you did not need to put much Cs in the bulb. Why not use it to recharge an alkali metal lamp? cheers, Neville Michie ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
It sounds like you need to dip a corner of the device in liquid nitrogen and allow the metal to evaporate and condense in the cold corner. Or is it sublimation. I do not know how long it would take. cheers, Neville Michie On 13/01/2011, at 11:31 PM, Chuck Harris wrote: I suppose that would be possible if a C beam standard worked like a rubidium reference, but alas, they are different in virtually all respects. Think of the C beam as having a small kettle full of cesium that is put on a low simmer. The kettle keeps the cesium molten, and bubbling up minute amounts of cesium vapor. How are you going to refill the kettle when it lives in the middle of a hard vacuum chamber? The best you could do with your technique (assuming it is even possible) is to coat the walls of the vacuum chamber with cesium... Kind of like trying to fill the gas tank by hosing the car down with gasoline. Besides, if HP can be believed, the kettle never runs out of cesium before the receiving end of the tube gets completely choked on waste cesium metal. That waste cesium needs to be removed, and the electron multiplier needs to be restored, at a minimum and the ion pump is probably full up too. -Chuck Harris Neville Michie wrote: It may not be necessary to open a tube to renew the supply of an alkali metal. I remember an experiment where an incandescent light bulb was dipped into molten sodium chloride in an iron vessel. The filament was run and a voltage between the filament and the iron vessel caused sodium ions to migrate through the glass into the bulb. Sodium accumulated in the bulb. It is obviously a slow process, but then you did not need to put much Cs in the bulb. Why not use it to recharge an alkali metal lamp? cheers, Neville Michie ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/ time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Really interesting thread. About a year ago on this thread the same discussion occurred. Several thoughts along these lines and frankly I know little accept for what I read here and online. I would agree the CS never runs out. Accept for one minor point. We tend to get these things way beyond HPs end dates by many years. So is it really true? This threads a bit different then the last one. The last one described opening the internals and various effects from trying to refill the kettle. This would be the first insight that I have in the fact that the systems polluted perhaps. Regards On Thu, Jan 13, 2011 at 7:31 AM, Chuck Harris cfhar...@erols.com wrote: I suppose that would be possible if a C beam standard worked like a rubidium reference, but alas, they are different in virtually all respects. Think of the C beam as having a small kettle full of cesium that is put on a low simmer. The kettle keeps the cesium molten, and bubbling up minute amounts of cesium vapor. How are you going to refill the kettle when it lives in the middle of a hard vacuum chamber? The best you could do with your technique (assuming it is even possible) is to coat the walls of the vacuum chamber with cesium... Kind of like trying to fill the gas tank by hosing the car down with gasoline. Besides, if HP can be believed, the kettle never runs out of cesium before the receiving end of the tube gets completely choked on waste cesium metal. That waste cesium needs to be removed, and the electron multiplier needs to be restored, at a minimum and the ion pump is probably full up too. -Chuck Harris Neville Michie wrote: It may not be necessary to open a tube to renew the supply of an alkali metal. I remember an experiment where an incandescent light bulb was dipped into molten sodium chloride in an iron vessel. The filament was run and a voltage between the filament and the iron vessel caused sodium ions to migrate through the glass into the bulb. Sodium accumulated in the bulb. It is obviously a slow process, but then you did not need to put much Cs in the bulb. Why not use it to recharge an alkali metal lamp? cheers, Neville Michie ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
On 1/13/11 4:59 AM, paul swed wrote: Really interesting thread. About a year ago on this thread the same discussion occurred. Several thoughts along these lines and frankly I know little accept for what I read here and online. I would agree the CS never runs out. Accept for one minor point. We tend to get these things way beyond HPs end dates by many years. So is it really true? The mfr end date is a guaranteed to work under all conditions and usage patterns date. I could easily see the various mechanisms leading to end of life proceeding at different rates depending on use, piece to piece variation, etc. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
You might find it interesting to look up the vapor pressure of cesium at room temperature. To get the cesium to transport from where it has deposited to your cold corner would require heating the whole tube up to where the cesium would vaporize. I can't help but think that heating everything in the tube that hot might cause other collateral damage... and the cesium would certainly go and plate out on even more exciting places than it did in normal operation. That might not be a good thing. I think this is a pay-to-play sort of thing. If you want to play with a C-beam, you are going to have to pay. If you want one that works like new, unless you are lucky, you might have to pay a lot. -Chuck Harris Neville Michie wrote: It sounds like you need to dip a corner of the device in liquid nitrogen and allow the metal to evaporate and condense in the cold corner. Or is it sublimation. I do not know how long it would take. cheers, Neville Michie ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion - How to make a tube
Sure it would be lots of fun making your own tube or rebuilding a bad one. This, my favorite internet video, is not exactly about caesium beam tubes, but at least shows some of the required skills, as well as how much fun it can be. http://dailymotion.alice.it/video/x3wrzo_fabrication-dune-lampe-triode_tech Adrian Tom Van Baak schrieb: Now that we are discussing how to restore Rb lamps. Has anyone given any thought to refilling or refluxing the Cs in depleted Cs tubes? Oh yes, after I ran into my first dead Cs and found the price of a replacement tube, you bet I wondered if they could be refilled. I mean, the same hp also made printers and you can refill them. What could be more natural. But a couple of events over the years dashed all my hopes. First I got my first opened Cs tube, from an 5061A that Corby had. I have no idea how you'd open one, do the brain surgery, and put it back together with the same purity and mechanical precision that it first was. Second, running out of cesium is not always the problem. Think about where the cesium goes. When a printer runs out of ink it's because it has printed tens of thousands of pages. The pages take the ink with them and the printer stays fairly clean. But where does the cesium go? It's all still inside, every single atom of it. On the walls, on the magnets, in the getter, and stuck on the dynodes of the electron multiplier. So even if you could add more Cs to the oven on one end, perhaps the harder job would be to clean up all the cesium residue that's everywhere else. It would be like adding more and more fresh oil to a car but never emptying the oil pan. Third, I got a tour of the hp factory in Santa Clara where the tubes were made. I was humbled. The clean room, the precision, the tiny EM, the vacuum stuff, the oven assembly, the one-time diaphragm that seals the oven pin hole, the wiring, the testing, the people, the decades of knowledge, the infrastructure. Instead what would be fun is for someone to try to make their own tube. Save yourself some work and re-use all the electronics of a 5061A. But make your own tube. Even re-use as many parts of an existing tube as you want. But make your own instead of trying to put Humpty Dumpty back together again. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
As I said last go-round, I think the chances of rebuilding an HP Cs tube are slim to none. BUT, if you were really dedicated, I think you could build up the physics package from pretty much standard stuff, like the Kimball Physics gun parts and Conflat SS vacuum hardware, etc. Check Duniway. I'd start by reviewing the old, academic papers. Much of the electronics can be bought on eBay as instruments now. Yes, it'd be refrigerator size, but it is do-able, IMO. Best, -John == ] You might find it interesting to look up the vapor pressure of cesium at room temperature. To get the cesium to transport from where it has deposited to your cold corner would require heating the whole tube up to where the cesium would vaporize. I can't help but think that heating everything in the tube that hot might cause other collateral damage... and the cesium would certainly go and plate out on even more exciting places than it did in normal operation. That might not be a good thing. I think this is a pay-to-play sort of thing. If you want to play with a C-beam, you are going to have to pay. If you want one that works like new, unless you are lucky, you might have to pay a lot. -Chuck Harris Neville Michie wrote: It sounds like you need to dip a corner of the device in liquid nitrogen and allow the metal to evaporate and condense in the cold corner. Or is it sublimation. I do not know how long it would take. cheers, Neville Michie ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion - DIY Cs
Hi I certainly agree with that. The tubes in a portable cesium are done so they fit inside a specific box. In a lot of ways bigger is better if you are going to do it yourself. It would not at all be a trivial undertaking. It also would not be cheap. Cs standards with dead tubes are indeed pretty cheap. I think I'd start with the electronics from one of them. Being able to do the tube stuff without having to do the electronics at the same time should make things a bit easier. You could swap out the electronics for your own once the tube was doing it's thing. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. Forster Sent: Thursday, January 13, 2011 11:24 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] CS reservoir depletion As I said last go-round, I think the chances of rebuilding an HP Cs tube are slim to none. BUT, if you were really dedicated, I think you could build up the physics package from pretty much standard stuff, like the Kimball Physics gun parts and Conflat SS vacuum hardware, etc. Check Duniway. I'd start by reviewing the old, academic papers. Much of the electronics can be bought on eBay as instruments now. Yes, it'd be refrigerator size, but it is do-able, IMO. Best, -John == ] You might find it interesting to look up the vapor pressure of cesium at room temperature. To get the cesium to transport from where it has deposited to your cold corner would require heating the whole tube up to where the cesium would vaporize. I can't help but think that heating everything in the tube that hot might cause other collateral damage... and the cesium would certainly go and plate out on even more exciting places than it did in normal operation. That might not be a good thing. I think this is a pay-to-play sort of thing. If you want to play with a C-beam, you are going to have to pay. If you want one that works like new, unless you are lucky, you might have to pay a lot. -Chuck Harris Neville Michie wrote: It sounds like you need to dip a corner of the device in liquid nitrogen and allow the metal to evaporate and condense in the cold corner. Or is it sublimation. I do not know how long it would take. cheers, Neville Michie ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Really interesting thread. About a year ago on this thread the same discussion occurred. Several thoughts along these lines and frankly I know little accept for what I read here and online. I would agree the CS never runs out. Accept for one minor point. We tend to huh? get these things way beyond HPs end dates by many years. So is it really true? This threads a bit different then the last one. The last one described opening the internals and various effects from trying to refill the kettle. This would be the first insight that I have in the fact that the systems polluted perhaps. Regards Paul, What I've heard is that the lifetime of the 5071A high-performance tube is around 7 years (when the cesium runs out) and the lifetime of the standard tube is up to 20 years (when the EM fails). There are other failure modes too so YMMV. Not sure about 5061A and other tubes. There are variations within the 5071A tube as well (including the short-lived turbo tube), so take this only as a rough estimate (but do see the chart in paper10.pdf below). As you may know the high-perf tubes have higher performance simply because they use a much higher flux of atoms (beam clock noise is a simple function of flux) and so they run out of gas proportionally faster. Like a candle burning twice as bright, or for you Neil fans, it's better to burn out than to fade away. But there's lots of data on this subject since most of the national timing laboratories use 5071A in quantity and they collect all the internal performance data that the 5071A makes available over the RS232 port. Some papers on the subject include: End-of-life Indicators for NIMA's High-performance Cesium Frequency Standards http://tycho.usno.navy.mil/ptti/ptti2002/paper10.pdf Maintenance of HP 5071A Primary Frequency Standards at USNO http://tycho.usno.navy.mil/ptti/1997/Vol%2029_06.pdf An Automated Alarm Program for HP5071A Frequency Standards http://tycho.usno.navy.mil/ptti/ptti99/PTTI_1999_649.PDF /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Hi Tom been quite a while hope you are well. The never run out comments, not from me. Look at the previous thread I tagged onto. My humor is that most of the CS tubes we get are very long in the tooth usually way past whatever anyone would say they are good for. However my 5065 Rb is still going strong, knock on wood after 2 X what was stated for life. Unfortunately my 5061 was actually dead on arrival. But you take your risk at $125, right? Didn't really matter that it did not work as much as I might have liked it to. I learned a heck of a lot from trying to get it to. Also from support on this list. If it had worked I would not have really learned a thing. Maybe I will find a tube one day. But pretty sure I won't be drilling a hole and pouring some CS into it. Oddly enough I picked up a HP super-duper pico amp meter and source and when the dust settles on several projects will hook it up just for the heck of it to see if there is even a drop of I beam current hiding behind some magnets in the tube. Regards Paul WB8TSL On Thu, Jan 13, 2011 at 2:30 PM, Tom Van Baak t...@leapsecond.com wrote: Really interesting thread. About a year ago on this thread the same discussion occurred. Several thoughts along these lines and frankly I know little accept for what I read here and online. I would agree the CS never runs out. Accept for one minor point. We tend to huh? get these things way beyond HPs end dates by many years. So is it really true? This threads a bit different then the last one. The last one described opening the internals and various effects from trying to refill the kettle. This would be the first insight that I have in the fact that the systems polluted perhaps. Regards Paul, What I've heard is that the lifetime of the 5071A high-performance tube is around 7 years (when the cesium runs out) and the lifetime of the standard tube is up to 20 years (when the EM fails). There are other failure modes too so YMMV. Not sure about 5061A and other tubes. There are variations within the 5071A tube as well (including the short-lived turbo tube), so take this only as a rough estimate (but do see the chart in paper10.pdf below). As you may know the high-perf tubes have higher performance simply because they use a much higher flux of atoms (beam clock noise is a simple function of flux) and so they run out of gas proportionally faster. Like a candle burning twice as bright, or for you Neil fans, it's better to burn out than to fade away. But there's lots of data on this subject since most of the national timing laboratories use 5071A in quantity and they collect all the internal performance data that the 5071A makes available over the RS232 port. Some papers on the subject include: End-of-life Indicators for NIMA's High-performance Cesium Frequency Standards http://tycho.usno.navy.mil/ptti/ptti2002/paper10.pdf Maintenance of HP 5071A Primary Frequency Standards at USNO http://tycho.usno.navy.mil/ptti/1997/Vol%2029_06.pdf An Automated Alarm Program for HP5071A Frequency Standards http://tycho.usno.navy.mil/ptti/ptti99/PTTI_1999_649.PDF /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
On 13/01/11 17:24, J. Forster wrote: As I said last go-round, I think the chances of rebuilding an HP Cs tube are slim to none. BUT, if you were really dedicated, I think you could build up the physics package from pretty much standard stuff, like the Kimball Physics gun parts and Conflat SS vacuum hardware, etc. Check Duniway. I'd start by reviewing the old, academic papers. Much of the electronics can be bought on eBay as instruments now. Yes, it'd be refrigerator size, but it is do-able, IMO. Many of the pieces of a physical package can either be found off the shelf (ionizer/masspectrometer) or at least be hammered up fairly easily (microwave link) even if performance is far optimum. The cesium oven should also be fairly buildable. The C-field coil could certainly be built with some care. My-metal shields may take some effort. Outer shield is a challenge for vacuum performance and there is such a thing as high-vacuum nuts. Similarly the ionpump is off the shelf. The piece that I would not expect to be easy to buy or build is the A and B magnets which deflect wrong state atoms. Also, handle Cesium and breaking the Cesium ampule may be a bit of a challenge to get right. There is certainly be a bit of challenges to get something which works. Being able to get good performance would take many many years of experimentation and learning. The HP/Symmetricom efforts spans from the 60thies. Many steps of improvement, of which only some is found in papers and patents. But they have left such traces too. There are many practical solutions which can be learned from the archives. The electronics could either be to reuse a HP5061 or whateer is available, but most of it should not be all that hard depending on background. It would be a hell of a project. Just like building a H-maser. In comparision a Rubidium is much easier. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
I'm not so sure handling the Cs is all that different from handling Na. You basically distill it in glass from where you break the vial to where it wants to ultimately be, under high vacuum. Actually, moving Rb is essentially the same too. I'd imagine building a Cs unit might be a bit easier than an H MASER, but not by much. Certainly a Rb is easier. -John == On 13/01/11 17:24, J. Forster wrote: As I said last go-round, I think the chances of rebuilding an HP Cs tube are slim to none. BUT, if you were really dedicated, I think you could build up the physics package from pretty much standard stuff, like the Kimball Physics gun parts and Conflat SS vacuum hardware, etc. Check Duniway. I'd start by reviewing the old, academic papers. Much of the electronics can be bought on eBay as instruments now. Yes, it'd be refrigerator size, but it is do-able, IMO. Many of the pieces of a physical package can either be found off the shelf (ionizer/masspectrometer) or at least be hammered up fairly easily (microwave link) even if performance is far optimum. The cesium oven should also be fairly buildable. The C-field coil could certainly be built with some care. My-metal shields may take some effort. Outer shield is a challenge for vacuum performance and there is such a thing as high-vacuum nuts. Similarly the ionpump is off the shelf. The piece that I would not expect to be easy to buy or build is the A and B magnets which deflect wrong state atoms. Also, handle Cesium and breaking the Cesium ampule may be a bit of a challenge to get right. There is certainly be a bit of challenges to get something which works. Being able to get good performance would take many many years of experimentation and learning. The HP/Symmetricom efforts spans from the 60thies. Many steps of improvement, of which only some is found in papers and patents. But they have left such traces too. There are many practical solutions which can be learned from the archives. The electronics could either be to reuse a HP5061 or whateer is available, but most of it should not be all that hard depending on background. It would be a hell of a project. Just like building a H-maser. In comparision a Rubidium is much easier. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion - DIY Cs
On 13/01/11 18:27, Bob Camp wrote: Hi I certainly agree with that. The tubes in a portable cesium are done so they fit inside a specific box. In a lot of ways bigger is better if you are going to do it yourself. It would not at all be a trivial undertaking. It also would not be cheap. Cs standards with dead tubes are indeed pretty cheap. I think I'd start with the electronics from one of them. Being able to do the tube stuff without having to do the electronics at the same time should make things a bit easier. You could swap out the electronics for your own once the tube was doing it's thing. Hacking existing hardware to achieve a digital steering of C-field should not be too hard. The first patent I recall uses a RCA CD1802 processor for control. Essentially it adds a DDS, ADC (detector), DAC (OCXO EFC and C-field control) and processor. It would replace the normal modulated signal of typical cesium signals (12,6 MHz) and take the signal prior to classical detectors. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Magnus Danielson wrote: experimentation and learning. The HP/Symmetricom efforts spans from the 60thies. Many steps of improvement, of which only some is found in papers and patents. But they have left such traces too. There are many practical solutions which can be learned from the archives. HP once held an internal seminar several days long that covered only the aspects of the CBT that were not public. So realize that what you know is the tip of the iceberg. Rick Karlquist N6RK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
On 13/01/11 22:55, Rick Karlquist wrote: Magnus Danielson wrote: experimentation and learning. The HP/Symmetricom efforts spans from the 60thies. Many steps of improvement, of which only some is found in papers and patents. But they have left such traces too. There are many practical solutions which can be learned from the archives. HP once held an internal seminar several days long that covered only the aspects of the CBT that were not public. So realize that what you know is the tip of the iceberg. Oh yes. I *expect* that there is a lot of things to know that I don't know. I expect that there is a gazillion things to know to get decent shape beam going. Aiming for a getting it to lock up level is what a very handy hobbyist may aim for and maybe attain after a lot of work. There will be loads and loads of systematic effects, biases etc. So no, I do not think even the entry level is simple... I'm not that naive... It took several decades of development for a large set of talented guys to come to the HP5071A design. Much of the knowledge is certainly skills of the art which isn't shared lightly... and isn't learned lightly either... So I am fully aware that I see only a little of the iceberg. Just reading up on the publically available information from the number of design efforts made in various places should be humbling for anyone doing the exercise. You may learn a lot without being able to design a high performance system. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
J. Forster wrote: I'd imagine building a Cs unit might be a bit easier than an H MASER, but not by much. Certainly a Rb is easier. -John Other than the glassware, building an Rb is entirely possible in your garage, at least if you are a certifiable time nut. This is based on the HP 10816 mini-Rb I worked on circa 1980. It would be even easier now. The glassware is tricky only because you have to work with stuff that is more like fused quartz than glass. This is because regular glass can't deal with Rb very well. The other problem for the garage builder is that one of the Rb isotopes is slightly radioactive. Probably not OK to have in your garage. Rick Karlquist N6RK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Lead is slightly radioactive. Presumably the person building the device would either source the right isotope or just use an existing vapor container from an old unit. Of course if it was totally scratch built, I'd still just buy the right isotope. -Bob On Thu, Jan 13, 2011 at 4:18 PM, Rick Karlquist rich...@karlquist.comwrote: J. Forster wrote: I'd imagine building a Cs unit might be a bit easier than an H MASER, but not by much. Certainly a Rb is easier. -John Other than the glassware, building an Rb is entirely possible in your garage, at least if you are a certifiable time nut. This is based on the HP 10816 mini-Rb I worked on circa 1980. It would be even easier now. The glassware is tricky only because you have to work with stuff that is more like fused quartz than glass. This is because regular glass can't deal with Rb very well. The other problem for the garage builder is that one of the Rb isotopes is slightly radioactive. Probably not OK to have in your garage. Rick Karlquist N6RK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
The glassware part is outlined in Strong's Proceedures in Experimental Physics as I remember. It takes some skill, but it's not insurmountable. Best, -John = Lead is slightly radioactive. Presumably the person building the device would either source the right isotope or just use an existing vapor container from an old unit. Of course if it was totally scratch built, I'd still just buy the right isotope. -Bob On Thu, Jan 13, 2011 at 4:18 PM, Rick Karlquist rich...@karlquist.comwrote: J. Forster wrote: I'd imagine building a Cs unit might be a bit easier than an H MASER, but not by much. Certainly a Rb is easier. -John Other than the glassware, building an Rb is entirely possible in your garage, at least if you are a certifiable time nut. This is based on the HP 10816 mini-Rb I worked on circa 1980. It would be even easier now. The glassware is tricky only because you have to work with stuff that is more like fused quartz than glass. This is because regular glass can't deal with Rb very well. The other problem for the garage builder is that one of the Rb isotopes is slightly radioactive. Probably not OK to have in your garage. Rick Karlquist N6RK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
On 14/01/11 00:18, Rick Karlquist wrote: J. Forster wrote: I'd imagine building a Cs unit might be a bit easier than an H MASER, but not by much. Certainly a Rb is easier. -John Other than the glassware, building an Rb is entirely possible in your garage, at least if you are a certifiable time nut. This is based on the HP 10816 mini-Rb I worked on circa 1980. It would be even easier now. The glassware is tricky only because you have to work with stuff that is more like fused quartz than glass. This is because regular glass can't deal with Rb very well. The other problem for the garage builder is that one of the Rb isotopes is slightly radioactive. Probably not OK to have in your garage. To start with, Rb-87 has a half-life of 4,88E+10 years with negative beta-decay, i.e. an electron. It has been judged very hard to accumulate any large amounts of it in the body to build up to a unsafe dosage... you would pee it out before it got there... Also, I already have it in the garage and does not feel overly scared by it. I also have some Americum in a smoke-detector. There is also uranium in the ground, causing background radiation. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
On 14/01/11 00:23, Robert Darlington wrote: Lead is slightly radioactive. Presumably the person building the device would either source the right isotope or just use an existing vapor container from an old unit. Of course if it was totally scratch built, I'd still just buy the right isotope. If you go down the classical route you need Rb-87 (x2) and Rb-85. Also, you want buffer-gas. A more modern route would skip two of the glass containers (the Rb-87 lamp and the Rb-85 filtering cell) and inject the right excitation wavelength using a tuned laser diode. It would just create a different set of problems, but if you do not aim for perfection at first, then it should be handleable. So far the lasers I've seen capable of pulling it off isn't that cheap, but I haven't looked too much at it and I am not a tuneable laser expert... I would have to do a bit more reading up before attempting anything in that direction. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Not to mention radio calcium in your bones. -John = To start with, Rb-87 has a half-life of 4,88E+10 years with negative beta-decay, i.e. an electron. It has been judged very hard to accumulate any large amounts of it in the body to build up to a unsafe dosage... you would pee it out before it got there... Also, I already have it in the garage and does not feel overly scared by it. I also have some Americum in a smoke-detector. There is also uranium in the ground, causing background radiation. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
On 1/13/11 3:18 PM, Rick Karlquist wrote: J. Forster wrote: I'd imagine building a Cs unit might be a bit easier than an H MASER, but not by much. Certainly a Rb is easier. -John Other than the glassware, building an Rb is entirely possible in your garage, at least if you are a certifiable time nut. This is based on the HP 10816 mini-Rb I worked on circa 1980. It would be even easier now. The glassware is tricky only because you have to work with stuff that is more like fused quartz than glass. This is because regular glass can't deal with Rb very well. My glassblowing friends say that it's just a matter of getting comfortable with the oxyhydrogen torch (with a colorless flame). If you can work with Pyrex and a oxyPropane, it's easier. They all say that this is a basic life skill that everyone should have. Yeah, sure. The other problem for the garage builder is that one of the Rb isotopes is slightly radioactive. Probably not OK to have in your garage. Pshaw.. we've all got Americium in our houses, what's the big deal. grin My (17 yr old) daughter is intrigued by the whole discussion on the rad-safe list about K40. Do you sleep on top of, under, or next to your partner to minimize radiation exposure. Does the amount of banana consumption of either person affect this? (as a father, I'm not so sure I'm comfortable with the whole discussion. As far as I'm concerned, she's taking a lead envelope to the dorms to sleep in.) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Also, I already have it in the garage and does not feel overly scared by it. I also have some Americum in a smoke-detector. There is also uranium in the ground, causing background radiation. yes, all true, but this is what causes my wife to worry that she will come home from work and find a crew in bunny suits outside our house. When I was an undergrad at UCLA, the local chapter of the Committee to Bridge the Gap made radiation measurements on the roof of Boelter Hall (wherein there was a decommissioned reactor) and discovered bigger than nominal background . Their excitement was tempered when it was discovered that the aggregate used in the concrete was granite from from the local mountains, which has a moderately high concentration of hornblende, and, hence has about double the usual background emissions. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
My glassblowing friends say that it's just a matter of getting comfortable with the oxyhydrogen torch (with a colorless flame). If you can work with Pyrex and a oxyPropane, it's easier. They all say that this is a basic life skill that everyone should have. Yeah, sure. There seems to be a bunch of standard techniques, then it's just a lot of practice. But, like cooking or sex, a good lab instructor is a big help. My (17 yr old) daughter is intrigued by the whole discussion on the rad-safe list about K40. Do you sleep on top of, under, or next to your partner to minimize radiation exposure. Does the amount of banana consumption of either person affect this? (as a father, I'm not so sure I'm comfortable with the whole discussion. As far as I'm concerned, she's taking a lead envelope to the dorms to sleep in.) A lead sleeping might protect her from real, rather than imagined, risks. YMMV, -John == ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
On 1/13/11 2:24 PM, Magnus Danielson wrote: On 13/01/11 22:55, Rick Karlquist wrote: Magnus Danielson wrote: experimentation and learning. The HP/Symmetricom efforts spans from the 60thies. Many steps of improvement, of which only some is found in papers and patents. But they have left such traces too. There are many practical solutions which can be learned from the archives. HP once held an internal seminar several days long that covered only the aspects of the CBT that were not public. So realize that what you know is the tip of the iceberg. Oh yes. I *expect* that there is a lot of things to know that I don't know. and it's reporting on a list like this that moves info from the known only to the cognoscenti inside company X to known to the initiated few who subscribe to time-nuts ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
On 14/01/11 02:25, jimlux wrote: Also, I already have it in the garage and does not feel overly scared by it. I also have some Americum in a smoke-detector. There is also uranium in the ground, causing background radiation. yes, all true, but this is what causes my wife to worry that she will come home from work and find a crew in bunny suits outside our house. When I was an undergrad at UCLA, the local chapter of the Committee to Bridge the Gap made radiation measurements on the roof of Boelter Hall (wherein there was a decommissioned reactor) and discovered bigger than nominal background . Their excitement was tempered when it was discovered that the aggregate used in the concrete was granite from from the local mountains, which has a moderately high concentration of hornblende, and, hence has about double the usual background emissions. Having had a party in Swedens first reactor R1, now de-commissioned research and educational reactor, I kind of should have worried before. Fact is... radiation wise it is one of the safer places to be, as they have measured every square meter separately to ensure that it is only background radiation left. They now use that reactor hall for dance and music performances. Quite central in Stocholm actually... We are straying too far away I fear. End story is that the small amounts of Rubidium we play with isn't very dangerous radiation-wise. I worry more about the fact that it would not be too nice to have direct contact with it as it reacts hefty with water and the result of that isn't all that nice. There is a thad of toxity too, but not very severly. I worry more about the fumes from the PCBs I solder and the lead in the solder... but usually not much at all. It seems like suitable lasers for pumping Rubidium can be found cheap... on ebay. Nice reference: http://massey.dur.ac.uk/resources/pfgriffin/griffin_thesis.pdf Points to Sharp GH0781JA2C, datasheet http://www.chipcatalog.com/Sharp_Microelectronics/GH0781JA2C.htm 2,80 USD each on ebay... well, why not get some and play a little? Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Magnus, That's a very interesting paper. It has some interesting stuff on the vacuum techniuque that's needed for Rb or more for Cs. Do you know if anybody has actually built / is selling a Rb with a diode light source, rather than the bulb? Best, -John It seems like suitable lasers for pumping Rubidium can be found cheap... on ebay. Nice reference: http://massey.dur.ac.uk/resources/pfgriffin/griffin_thesis.pdf Points to Sharp GH0781JA2C, datasheet http://www.chipcatalog.com/Sharp_Microelectronics/GH0781JA2C.htm 2,80 USD each on ebay... well, why not get some and play a little? Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
On 14/01/11 03:07, J. Forster wrote: Magnus, That's a very interesting paper. It has some interesting stuff on the vacuum techniuque that's needed for Rb or more for Cs. Do you know if anybody has actually built / is selling a Rb with a diode light source, rather than the bulb? Not to my knowledge. However, they have been hacked for experimental purposes: http://tycho.usno.navy.mil/ptti/ptti2003/poster16.pdf There is more on the topic, such as: http://www.pttimeeting.org/archivemeetings/2009papers/poster6.pdf http://tf.nist.gov/general/pdf/972.pdf http://doc.rero.ch/lm.php?url=1000,43,4,20101230154956-BF/Affolderbach_Christoph_-_Experimental_Demonstration_of_a_Compact_and_High-Performance_20101230.pdf http://ixnovi.people.wm.edu/documents/NathanBelcherREUPaper.pdf A particular trick is to apply the RF onto the driving laser and do away with the resonant cavity that way. The chip scale cesium clocks is doing the same thing. Essentially it is a new type of physical package, where the (cesium) beam, (H) active maser bounce box and (Rb) gas cells has been the classical precursors. Another strain of development is naturally the ion-traps. There is research in the field, and I am only googling along and reading some papers every now and then. But as things progresses, the size of a rubidium physical package shrinks a lot when the it comes into production. Maybe some of the tiny onces already taken the step by now. The OCXO package can become the large part... :) Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion - Where to buy a tube?
Not lately I seem to remember $12K or 30K something crazy like that. Somewhat out of an Amateurs budget. Though I should get the lotto any day now. On Thu, Jan 13, 2011 at 8:28 PM, Shawn Tayler sh...@xmtservices.net wrote: So, Has anyone priced a replacement for a 5061 tube lately? I thought I saw upgrade kits from one of the other vendors in magazine once. Where does that path take you? Anyone? Shawn On Thu, 2011-01-13 at 15:02 +0100, Adrian wrote: Sure it would be lots of fun making your own tube or rebuilding a bad one. This, my favorite internet video, is not exactly about caesium beam tubes, but at least shows some of the required skills, as well as how much fun it can be. http://dailymotion.alice.it/video/x3wrzo_fabrication-dune-lampe-triode_tech Adrian Tom Van Baak schrieb: Now that we are discussing how to restore Rb lamps. Has anyone given any thought to refilling or refluxing the Cs in depleted Cs tubes? Oh yes, after I ran into my first dead Cs and found the price of a replacement tube, you bet I wondered if they could be refilled. I mean, the same hp also made printers and you can refill them. What could be more natural. But a couple of events over the years dashed all my hopes. First I got my first opened Cs tube, from an 5061A that Corby had. I have no idea how you'd open one, do the brain surgery, and put it back together with the same purity and mechanical precision that it first was. Second, running out of cesium is not always the problem. Think about where the cesium goes. When a printer runs out of ink it's because it has printed tens of thousands of pages. The pages take the ink with them and the printer stays fairly clean. But where does the cesium go? It's all still inside, every single atom of it. On the walls, on the magnets, in the getter, and stuck on the dynodes of the electron multiplier. So even if you could add more Cs to the oven on one end, perhaps the harder job would be to clean up all the cesium residue that's everywhere else. It would be like adding more and more fresh oil to a car but never emptying the oil pan. Third, I got a tour of the hp factory in Santa Clara where the tubes were made. I was humbled. The clean room, the precision, the tiny EM, the vacuum stuff, the oven assembly, the one-time diaphragm that seals the oven pin hole, the wiring, the testing, the people, the decades of knowledge, the infrastructure. Instead what would be fun is for someone to try to make their own tube. Save yourself some work and re-use all the electronics of a 5061A. But make your own tube. Even re-use as many parts of an existing tube as you want. But make your own instead of trying to put Humpty Dumpty back together again. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
J. Forster wrote: Magnus, That's a very interesting paper. It has some interesting stuff on the vacuum techniuque that's needed for Rb or more for Cs. Do you know if anybody has actually built / is selling a Rb with a diode light source, rather than the bulb? Kernco, Symmetricom. Best, -John Bruce It seems like suitable lasers for pumping Rubidium can be found cheap... on ebay. Nice reference: http://massey.dur.ac.uk/resources/pfgriffin/griffin_thesis.pdf Points to Sharp GH0781JA2C, datasheet http://www.chipcatalog.com/Sharp_Microelectronics/GH0781JA2C.htm 2,80 USD each on ebay... well, why not get some and play a little? Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Hi Tom been quite a while hope you are well. The never run out comments, not from me. Look at the previous thread I tagged onto. My humor is that most of the CS tubes we get are very long in the tooth usually way past whatever anyone would say they are good for. That is so true. It always amazes to pick up a 30 year old 5061A and find that it still works. Sometimes the reason is that it is already on its 2nd or 3rd replacement tube before it went to surplus. In which case you're happy for years. Other times it may be that the 5061A was used only very intermittently and the tube is the low S/N original. A real gem would be one that was kept in cs-off mode except for a few hours once a month to keep the OCXO within some loose cal lab spec. Even after decades it would be as good as new. For many frequency applications there is no reason to run in full cs-locked mode. This is also true if you need good short-term stability. The free-running OCXO in most Cs (and GPSDO for that matter) are more stable short-term when the loop is open. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Scott, Just being a high vacuum nut may not be enough. Most vacuum devices have getters engineered into them. These are usually reactive coatings applied to the cavity wall that react with or absorb trace gasses to maintain the vacuum. They are made of evaporated thin-films of exotic mixtures like zirconium and vanadium, aluminum, cobalt, etc... If you've ever seen a glass vacuum tube with a mirror top coating, you've seen a getter. The act of opening them in a high vacuum environment, may not destroy them, but introducing them to an any kind of atmosphere to perform a repair may destroy the getters, and render the life of the device quite short. Rob Ex-USGS Isotope branch Vacuum Nut On Jan 11, 2011, at 6:06 PM, scmcgr...@gmail.com wrote: Now that we are discussing how to restore Rb lamps. Has anyone given any thought to refilling or refluxing the Cs in depleted Cs tubes? Obviously opening would require high vaccum equipment - which is a totally separate category of nut (Or is it?) Scott Scott Sent from my Verizon Wireless BlackBerry ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/ time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
This is a popular FAQ that Cs engineers hear. The correct answer (at least for HP/Agilent CBTs) is that there is plenty of Cs in the tube, and they don't fail because they ran out of Cs. Something else will always wear out first. Regarding the general idea of rebuilding CBT's: a used CBT is so cesiated that it is not practical to rebuild it even on the regular CBT line. Even if it were, it is unlikely a time nut would have the necessary high vacuum equipment. It is pretty serious stuff. You also need to be able to laser weld the case together when you are finished. Sure seems like a don't try this at home thing. We're still waiting to see if they can figure out how make 5071 CBT's on the east coast, let alone someone's garage. Rick Karlquist N6RK On 1/11/2011 4:06 PM, scmcgr...@gmail.com wrote: Now that we are discussing how to restore Rb lamps. Has anyone given any thought to refilling or refluxing the Cs in depleted Cs tubes? Obviously opening would require high vaccum equipment - which is a totally separate category of nut (Or is it?) Scott Scott Sent from my Verizon Wireless BlackBerry ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
Now that we are discussing how to restore Rb lamps. Has anyone given any thought to refilling or refluxing the Cs in depleted Cs tubes? Oh yes, after I ran into my first dead Cs and found the price of a replacement tube, you bet I wondered if they could be refilled. I mean, the same hp also made printers and you can refill them. What could be more natural. But a couple of events over the years dashed all my hopes. First I got my first opened Cs tube, from an 5061A that Corby had. I have no idea how you'd open one, do the brain surgery, and put it back together with the same purity and mechanical precision that it first was. Second, running out of cesium is not always the problem. Think about where the cesium goes. When a printer runs out of ink it's because it has printed tens of thousands of pages. The pages take the ink with them and the printer stays fairly clean. But where does the cesium go? It's all still inside, every single atom of it. On the walls, on the magnets, in the getter, and stuck on the dynodes of the electron multiplier. So even if you could add more Cs to the oven on one end, perhaps the harder job would be to clean up all the cesium residue that's everywhere else. It would be like adding more and more fresh oil to a car but never emptying the oil pan. Third, I got a tour of the hp factory in Santa Clara where the tubes were made. I was humbled. The clean room, the precision, the tiny EM, the vacuum stuff, the oven assembly, the one-time diaphragm that seals the oven pin hole, the wiring, the testing, the people, the decades of knowledge, the infrastructure. Instead what would be fun is for someone to try to make their own tube. Save yourself some work and re-use all the electronics of a 5061A. But make your own tube. Even re-use as many parts of an existing tube as you want. But make your own instead of trying to put Humpty Dumpty back together again. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
On 12/01/11 01:06, scmcgr...@gmail.com wrote: Now that we are discussing how to restore Rb lamps. Has anyone given any thought to refilling or refluxing the Cs in depleted Cs tubes? As it has been pointed out before, the failure of a tube may be from any number of issues, including the failure of the ionizer of the masspectrometer for instance. Restoring a tube may require cleaning or replacement several parts. Another failure may be the ion-pump. Regardless it may take some effort to clean things up. It's in the arcives if you search for it. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CS reservoir depletion
I have a CS tube that has a 'rattle'. I suspect one of the magnets has become dislodged. It would be nice to be able to 'reposition' the magnet if indeed that is the problem. I have thought about X-Raying it to see if I could see the problem. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of scmcgr...@gmail.com Sent: Tuesday, January 11, 2011 6:06 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] CS reservoir depletion Now that we are discussing how to restore Rb lamps. Has anyone given any thought to refilling or refluxing the Cs in depleted Cs tubes? Obviously opening would require high vaccum equipment - which is a totally separate category of nut (Or is it?) Scott Scott Sent from my Verizon Wireless BlackBerry ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
