Hi all, Murray Greenman wrote:
> ...I would imagine one of the reasons for > the limited use of the gamma ray technique is cost. > The irradiation is not done to get an ultimate aging, but to make such crystals more insensitive to the stronger gamma radiation (as mentioned in an earlier post). In addition, quartz material used for space-qualified oscillators is undergoing a so-called sweeping process, in which a high electrical D.C. field is applied to the quartz block (which is metallized with gold on two opposite surfaces), while the crystal is stored at elevated temperature and the D.C. current is monitored. The current decreases over time, and after a few days or weeks, when the current has gone down below a given limit, the sweeping procedure is stopped. This process removes foreign ions from the crystal lattice and makes therefore the crystal more insensitive to irradiation. With the mentioned additional gamma irradiation of the crystal unit, remaining ions are further "removed" and thus the crystal becomes more immune against space radiation. Regards Bernd Neubig DK1AG _______________________________________________ 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.
