QUARTZ CRYSTAL AGING EFFECTS.
Quarterly rept. no. 5, 15 Feb-15 May 64,
GEORGIA INST OF TECH ATLANTA ENGINEERING EXPERIMENT STATION
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Data on the aging of 3 Mc and 16 Mc AT-cut quartz resonators are summarized. The aging rates of precision 3 Mc resonators of natural, swept, cultured, and swept cultured quartz varied with the type of quartz. Aging rates ranged from 1 to 9 pp 10 to the 8th powerwk initially but decreased to 0.2 to 3 pp 10 to the 8th powerwk after 20 weeks. The average aging rate of unswept cultured quartz alone remained 1 pp 10 to the 8th power wk. 16 Mc resonators irradiated at SPRF 10000 rads of gamma 9 x 10 to the 13th power nvt or exposed to a Cs 137 gamma source 10000 rads of gamma exhibited shifts in frequency of a few parts in 10 to the 7th power. The shifts were negative for natural quartz, positive for cultured quartz, and very small for the swept cultured quartz. X-ray source image distortion SID patterns have been made of low frequency and 10 Mc resonators of typical and atypical aging behavior. Examples of scratches, twinning, strain, and other internal defects are exhibited. SID patterns of 10 Mc resonators of poor aging behavior have revealed a number of units with defects leading into the central zone of the quartz plates. SID patterns made of low frequency resonators revealed the normal driven zones of a 455 Kc DT cut resonator and an abnormal pattern for a unit with a large defect zone near one end.