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Text Box: Fractional Frequency, ppb
Fractional Frequency, ppb
10
0
-10
-20
-30
-40
10
102
103
104
105
106
Dose, rad(SiO2)
1. Initial irradiation
2.  Reirradiation (after 2.5 x 104 rad)
3.  Reirradiation (after >106 rad)
Five irradiations; responses during the 4th and 5th irradiations repeated the results of the 3rd. At least 2 days elapsed between successive irradiations.
Initial slopes:
1st:      -1 x 10-9/rad
2nd:    +1 x 10-11/rad
3rd:     +3  x 10-12/rad
4th:     +3  x 10-12/rad
5th:     +5  x 10-12/rad
Effects of Repeated Radiations
   In the experiments described in the reference, irradiation with X-rays and gamma rays from a cobalt-60 source gave similar results, thus confirming that a “rad is a rad”.  The initial irradiations resulted in negative shifts, subsequent irradiations resulted in smaller shifts.  The frequency changes vs. time for hours to days after the irradiations significantly exceeded the pre-irradiation aging rates.  Higher doses generally resulted in higher increases in aging rates.


L. J. Palkuti and Q. T. Truong, "An X-Ray Irradiation System for Total-Dose Testing of Quartz Resonators," Proc. 38th Annual Symposium on Frequency Control, pp. 55-62, 1984, AD-A217381.