4-83
10 MeV electrons,
5 MHz 5th overtone
AT-cut resonators
Z-growth
cultured
Swept Z-growth
cultured
Natural
Text Box: Frequency Change (Hz)
Frequency Change (Hz)
Reds (Si)
104                      5       105                       5        106                      5       107
50
30
10
0
-10
-30
-50
Radiation Induced Df vs. Dose and Quartz Type
   The steady-state frequency shifts due to ionizing radiation are due to radiation caused changes at impurity defects.  The defect of major concern in quartz is the substitutional Al3+ defect with its associated interstitial charge compensator, which can be an H+, Li+, or Na+ ion, or a hole.  This defect substitutes for a Si4+ in the quartz lattice (see chapter 5).  Radiation can result in a change in the position of weakly bound compensators, which changes the elastic constants of quartz and thereby leads to a frequency change.  The movement of ions also results in a decrease in the crystal's Q, i.e., in an increase in the crystal's equivalent series resistance, especially upon exposure to a pulse of ionizing radiation.  If the oscillator's gain margin is insufficient, the increased resistance can stop the oscillation for periods lasting many seconds.


B. R. Capone, A. Kahan, R. N. Brown, and J. R. Buckmelter, "Quartz Crystal Radiation Effects," IEEE Trans. Nuclear Sci., NS-17, pp. 217-221, 1970.

J. C. King and D. R. Koehler, Radiation Effects on Resonators. In: Precision Frequency Control, Vol. 2 (E. A. Gerber and A. Ballato, eds.), Academic Press, New York, pp. 147-159, 1985.

J. J. Suter, et al., “The Effects of Ionizing and Particle Radiation on Precision Frequency Sources,” Proc. 1992 IEEE Frequency Control Symposium, IEEE Cat. No. 92CH3083-3, 1992.

J. C. King and H. H. Sander, “Rapid Annealing of Frequency Change in High Frequency Crystal Resonators Following Pulsed X-irradiation at Room Temperature,” Proc. 27th Ann. Symp. Frequency Control, pp. 117-119, NTIS Accession No. AD-771042, 1973.

R. E. Paradysz, and W. L. Smith, “Crystal Controlled Oscillators for Radiation Environments,” Proc. 27th Ann. Symp. Frequency Control, pp. 120-123, NTIS Accession No. AD-771042, 1973.