[ccp4bb] X-Stream 2000 problem - ICING
Apologies for this slightly off topic question: I am having a great deal of trouble with my X-Stream 2000 cryostream system and I wondered if other users have similar problems. I've replaced almost all components (new GAST compressors, helium recharges, filters, etc., etc.) in the last couple of months but there is almost always icing of any cryo within 10 - 20 minutes of mounting a loop, and it is adversely affecting data collections. It appears like there is too much moisture in the cold or wam streams but the tubes have been fully dried out as per Rigaku advice. This X-Stream is attached to a generator with inverted phi axis and and i'm wondering if this could be the source of the problem, as the X-Stream for another generator in the same laboratory with normal phi axis does not ice up. Can some sort of turbulence around the loop caused by backdraft from the cryo hitting the inverted phi axis / camera mount cause excess humidity and lead to icing on the pin, loop and crystal? Has anyone else got this problem? Any suggestions would be very gratefully appreciated. Best Wishes, Mark _ Dr Mark Agacan Scientific Officer, Division of Biological Chemistry and Drug Discovery, Wellcome Trust Biocentre, College of Life Sciences, Dow St., University of Dundee, Dundee, DD1 5EH Tel: +44 1382 388751 Fax: +44 1382 345764 _ The University of Dundee is a registered Scottish charity, No: SC015096
Re: [ccp4bb] X-Stream 2000 problem - ICING
Hi Mark We had a LOT of pain with icing, and it really comes down to one thing: water in the gN2. And don't expect to measure some other way whether you have it, because your X-stream (or Cobra) is the most sensitive water meter there is. In our case, the symptom was the X-stream (and later Cobra) blocking up after between several days and several hours. And we solved it by ditching the gN2 generators we were using, and organising boil-off gN2 (much purer). The secondary effect of sample icing: we'd see this as well if we had something (e.g. collimator) poking into the cold stream*: that causes turbulence which draws in moisture. Worst case you see ice flakes flick onto the crystal in real time; best case you get an ice ball after a few minutes to hours. (* technically, the stationary phase between the cold and warm streams.) Hope that helps. phx Mark Agacan wrote: Apologies for this slightly off topic question: I am having a great deal of trouble with my X-Stream 2000 cryostream system and I wondered if other users have similar problems. I've replaced almost all components (new GAST compressors, helium recharges, filters, etc., etc.) in the last couple of months but there is almost always icing of any cryo within 10 - 20 minutes of mounting a loop, and it is adversely affecting data collections. It appears like there is too much moisture in the cold or wam streams but the tubes have been fully dried out as per Rigaku advice. This X-Stream is attached to a generator with inverted phi axis and and i'm wondering if this could be the source of the problem, as the X-Stream for another generator in the same laboratory with normal phi axis does not ice up. Can some sort of turbulence around the loop caused by backdraft from the cryo hitting the inverted phi axis / camera mount cause excess humidity and lead to icing on the pin, loop and crystal? Has anyone else got this problem? Any suggestions would be very gratefully appreciated. Best Wishes, Mark _ Dr Mark Agacan Scientific Officer, Division of Biological Chemistry and Drug Discovery, Wellcome Trust Biocentre, College of Life Sciences, Dow St., University of Dundee, Dundee, DD1 5EH Tel: +44 1382 388751 Fax: +44 1382 345764 _ The University of Dundee is a registered Scottish charity, No: SC015096
Re: [ccp4bb] X-Stream 2000 problem - ICING
Hi, If you have ice on the crystal (loop) but no blockages of the cryostream itself (and this seems to be what you're saying), it is unlikely to be a problem with the LN2 (although I only have experience with Oxford Crystreams, but I imagine this also applies to X-streams). Our main problems are turbulence (collimator poking into the gas stream(s) or gas 'bouncing' back from something just beyond the crystal - moving things even a little may help here) and drafts due to 'powerful' air-conditioning. As you state that one of your setups is affected and not the other, it may well be the case that an air conditioning vent is blowing onto your setup, and disturbing the gas streams. We resorted to hanging plastic sheeting around two sides of our set-up and this made a vast difference. HTH, Johan Mark Agacan wrote: Apologies for this slightly off topic question: I am having a great deal of trouble with my X-Stream 2000 cryostream system and I wondered if other users have similar problems. I've replaced almost all components (new GAST compressors, helium recharges, filters, etc., etc.) in the last couple of months but there is almost always icing of any cryo within 10 - 20 minutes of mounting a loop, and it is adversely affecting data collections. It appears like there is too much moisture in the cold or wam streams but the tubes have been fully dried out as per Rigaku advice. This X-Stream is attached to a generator with inverted phi axis and and i'm wondering if this could be the source of the problem, as the X-Stream for another generator in the same laboratory with normal phi axis does not ice up. Can some sort of turbulence around the loop caused by backdraft from the cryo hitting the inverted phi axis / camera mount cause excess humidity and lead to icing on the pin, loop and crystal? Has anyone else got this problem? Any suggestions would be very gratefully appreciated. Best Wishes, Mark _ Dr Mark Agacan Scientific Officer, Division of Biological Chemistry and Drug Discovery, Wellcome Trust Biocentre, College of Life Sciences, Dow St., University of Dundee, Dundee, DD1 5EH Tel: +44 1382 388751 Fax: +44 1382 345764 _ The University of Dundee is a registered Scottish charity, No: SC015096 -- + Dr. Johan P. Turkenburg X-ray facilities manager York Structural Biology Laboratory University of York Phone (+) 44 1904 328251 York YO10 5DD UK Fax (+) 44 1904 328266 +
Re: [ccp4bb] X-Stream 2000 problem - ICING
We've been able to run months with an old Xstream 2000 system, so that shouldn't be the problem. Unlike Frank, we haven't had problems with water in the nitrogen from a nitrogen generator. If Frank is correct, that it's water, then either the molecular sieves need to be replaced, or there is ice buildup and blockage in the coldhead. Usually blockage in the coldhead means that you can't get down in temp, or can't maintain it within 1 degree or less. We do bring the temp up, run it at RT over the weekend to dry things out, and then bring it down for routine cooling. If it's turbulence, then you don't have the warm and cold flow rates set correctly. One thing you can see immediately, upon getting down to 100K, is how far is the frosting plume from the tip of the nozzle. If you adjust the flow rates, you can move that plume, caused by turbulence, closer or further from the nozzle. It's also possible that there is something in the nozzle that is causing turbulence no matter what the flow rates are, and your vendor needs to look at that. Bernie Santarsiero On Mon, January 12, 2009 6:11 am, Frank von Delft wrote: Hi Mark We had a LOT of pain with icing, and it really comes down to one thing: water in the gN2. And don't expect to measure some other way whether you have it, because your X-stream (or Cobra) is the most sensitive water meter there is. In our case, the symptom was the X-stream (and later Cobra) blocking up after between several days and several hours. And we solved it by ditching the gN2 generators we were using, and organising boil-off gN2 (much purer). The secondary effect of sample icing: we'd see this as well if we had something (e.g. collimator) poking into the cold stream*: that causes turbulence which draws in moisture. Worst case you see ice flakes flick onto the crystal in real time; best case you get an ice ball after a few minutes to hours. (* technically, the stationary phase between the cold and warm streams.) Hope that helps. phx Mark Agacan wrote: Apologies for this slightly off topic question: I am having a great deal of trouble with my X-Stream 2000 cryostream system and I wondered if other users have similar problems. I've replaced almost all components (new GAST compressors, helium recharges, filters, etc., etc.) in the last couple of months but there is almost always icing of any cryo within 10 - 20 minutes of mounting a loop, and it is adversely affecting data collections. It appears like there is too much moisture in the cold or wam streams but the tubes have been fully dried out as per Rigaku advice. This X-Stream is attached to a generator with inverted phi axis and and i'm wondering if this could be the source of the problem, as the X-Stream for another generator in the same laboratory with normal phi axis does not ice up. Can some sort of turbulence around the loop caused by backdraft from the cryo hitting the inverted phi axis / camera mount cause excess humidity and lead to icing on the pin, loop and crystal? Has anyone else got this problem? Any suggestions would be very gratefully appreciated. Best Wishes, Mark _ Dr Mark Agacan Scientific Officer, Division of Biological Chemistry and Drug Discovery, Wellcome Trust Biocentre, College of Life Sciences, Dow St., University of Dundee, Dundee, DD1 5EH Tel: +44 1382 388751 Fax: +44 1382 345764 _ The University of Dundee is a registered Scottish charity, No: SC015096
Re: [ccp4bb] X-Stream 2000 problem - ICING
Mark, What bothers me about your message is that you already have talked to Rigaku. Until now we have never been able to create a problem that they could not diagnose and help me solve from remote. In danger of offending ccp4 readers: specialized Rigaku experts are a remarkable source for information and solutions, probably better than we are. Your most likely problem is that your nitrogen is not dry? Specifically, check your air dryer (sorry, nitrogen dryer) that it works appropriately. Very specifically, there reside two compressors inside the air dryer and if one no longer works, the quality of your nitrogen stream degrades. It may not be apparent if both compressors work, one can supply all the pressure and volume you need and is sufficiently noisy that you would not notice the second being silent. Of course this problem becomes obvious when you open up the cabinet. (Yes, of course this happened to us once before and in our case the compressor wiring was fickle, as in, working when the cabinet was open and not (always) working when the cabinet was closed; took FOREVER to find the problem.) Your second most likely reason is that the warm stream (outer stream) is not sufficiently protecting your cold stream from humidity, but this is not affected by your phi-axis position. We have two inverted phi-axes and we do not see icing, so there is no fundamental reason why the phi-axis should not be inverted. Mark ? -Original Message- From: Mark Agacan m.aga...@dundee.ac.uk To: CCP4BB@JISCMAIL.AC.UK Sent: Mon, 12 Jan 2009 3:42 am Subject: [ccp4bb] X-Stream 2000 problem - ICING Apologies for this slightly off topic question: I am having a great deal of trouble with my X-Stream 2000 cryostream system and I wondered if other users have similar problems. I've replaced almost all components (new GAST compressors, helium recharges, filters, etc., etc.) in the last couple of months but there is almost always icing of any cryo within 10 - 20 minutes of mounting a loop, and it is adversely affecting data collections. It appears like there is too much moisture in the cold or wam streams but the tubes have been fully dried out as per Rigaku advice. This X-Stream is attached to a generator with inverted phi axis and and i'm wondering if this could be the source of the problem, as the X-Stream for another generator in the same laboratory with normal phi axis does not ice up. Can some sort of turbulence around the loop caused by backdraft from the cryo hitting the inverted phi axis / camera mount cause excess humidity and lead to icing on the pin, loop and crystal? Has anyone else got this problem? Any suggestions would be very gratefully appreciated. Best Wishes, Mark _ Dr Mark Agacan Scientific Officer, Division of Biological Chemistry and Drug Discovery, Wellcome Trust Biocentre, College of Life Sciences, Dow St., University of Dundee, Dundee, DD1 5EH Tel: +44 1382 388751 Fax: +44 1382 345764 _ The University of Dundee is a registered Scottish charity, No: SC015096
