Mike Fahmie wrote: > Somewhere, I have a NASA pub that describes a technique using Gamma Rays > to > accelerate aging so that later aging is much reduced, can't seem to find > it > now. I would guess that the radiation cause the stresses to relax. NASA > was > evidently interested because satellites experience a lot more radiation > than we receive here on the surface and it probably caused a rapid > frequency shift in otherwise unradiated crystals.
I remember some of the crystal gurus talking about this. I suspect it didn't pan out or everyone would be doing it. I also remember them saying that radiation causes "color centers" to appear. > I have two HP quartz oscillators that I've been running and logging for > well over a decade. They run 24/7 and are on battery backup. The HP-103 > shows about 6 parts in 10^-12/day and the HP-107 about 2 parts in > 10^-13/day. I attribute this to steady temperature and solid mounting in a > heavy rack. > > -Mike- That's incredible Mike. I've never seen a 10811 or E1938 within a factor of 10 of the first number you gave, let alone the second. The second rate would be very respectible for a Rb standard. I believe those antique oscillators you have are using non-HP made xtals at 1 MHz (or 5 MHz at the most) in glass packages. While a steady temperature and solid mounting is great, it takes more than that to put up these kind of numbers. Congratulations, keep taking good care of those old war horses. I wish Len Cutler were still around to tell about it. He proudly keep a 107 prototype in his office. Len couldn't bring himself to design anything that wasn't a doomsday machine. Rick Karlquist, N6RK _______________________________________________ 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.
