Hi I would bet that they started as you have with a low oven setting and cranked it up based on stability data. Once they got to that point, add a bit to have enough margin on the tube for it to last the rated life.
Since there are multiple quantum “modes” the beam can get into, there may have been a bit of sweeping involved to keep this separated from that. If so, I suspect that the sweep procedure is long lost. You are pretty much stuck with the stability check / tweak / stability check approach. Bob > On Nov 9, 2016, at 7:02 PM, Skip Withrow <[email protected]> wrote: > > Hello Time-Nuts, > > I have been checking out some cesium beam tubes lately and have run into an > interesting one. The tube is a standard HP 05061-6077 unit. There are two > labels on these tubes, one at the end that has a serial number, and the > other large label on the side that has the operating information (and the > serial number). Problem with this tube is the large label is completely > BLANK. It appears that there was never any information on this label. The > source that it came from was pretty closely connected to HP, so it could be > a tube that escaped before testing/characterization. > > The nice thing is that it works! Using some random nominal resistors for > the oven temperature I get good beam current. Changing the electron > multiplier voltage also dramatically changes the beam current. I see the 3 > peaks around the on-frequency point quite nicely. > > So, the question is - how do I determine the operating point of the tube > with no data? I could fire up a known tube and set the beam current for > the same value, but how would the oven temperature vs. electron multiplier > voltage be resolved. I would think that a lower oven temp and higher EM > voltage would give the same beam current as a higher oven temp and lower EM > voltage. > > I'm sure the HP did not do any characterization of the tube until it was > all buttoned up. So how did they determine the temperature of the oven? > Just from the value of the internal thermistor? > > I suspect the answer is what kind of S/N ratio do I want? If that is the > case then I would be tempted to run at the lowest oven temp and highest EM > voltage that gave me a usable signal - for the sake of tube life. > > Any thoughts? > > Thanks, > Skip Withrow > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
