Evaluation of Mechanisms for Low-Dose Frequency Shifts in Crystal Oscillators

Flanagan, T.M.; Leadon, R. E.; Shannon, D.L.

doi:10.1109/freq.1986.200932

Cited by 10 publications

(4 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Much larger frequency alterations are experienced by crystals when irradiated by natural radiation in space [5]. Numerous studies on the radiation susceptibilities of crystal material and crystal resonators have therefore been conducted [6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Low Dose Rate Proton Irradiation of Quartz Crystal Resonators

Koga¹,

Looper²,

Pinkerton³

et al. 1998

View full text Add to dashboard Cite

show abstract

Section: Introductionmentioning

confidence: 99%

“…6) A large change in frequency per rad occurs at low dose rates [6]. 7) The exact cause of degradation is not well known [5,9].…”

Section: Introductionmentioning

confidence: 99%

Low Dose Rate Proton Irradiation of Quartz Crystal Resonators

Koga¹,

Looper²,

Pinkerton³

et al. 1998

View full text Add to dashboard Cite

show abstract

“…The low dose radiation effects are not well wrderstood. The frequency changes pet rad at low doses can be several orders of magnitude higher than at high doses [135]; sensitivity as high as 1 X per rad has been reported upon initial irradiations [110]. A resonator with such sensitivity would exhibit apparent aging (i.e., drift, according to the new definitions [2]) of 1 X 10"O per year or 3 X per day due to the background radiation.…”

Section: Several Authors Have Reported Few Parts In 10l2 Per Day Aginmentioning

confidence: 99%

The aging of bulk acoustic wave resonators, filters and oscillators

Vig

Meeker²

Proceedings of the 45th Annual Symposium on Frequency Control 1991

View full text Add to dashboard Cite

“…Norton, Cloeren, and Suter; Suter and Maurer; and Suter have recently reported low-dose frequency offset studies [11,12,13]. Several mechanisms for low-dose effects have been discussed by Flanagan, Leadon, and Shannon [14]. Palkuti and Truong ( 1 5 1 have described an automated radiation test facility, The frequency of the thickness-shear mode used in rotated Y-plates and similar crystals is given by…”

mentioning

confidence: 95%

Radiation induced frequency offsets and acoustic loss in AT-cut quartz crystals

Martin

Proceedings of the 43rd Annual Symposium on Frequency Control

View full text Add to dashboard Cite

Ionizing radiation modifies point defects already present in quartz. For example, the A1-Li center present in as-grown high quality cultured quartz is converted into a mixture of Al-OH and Al-hole centers. While neither the A1-Li nor the A1-OH center have acoustic l o s s peaks, peaks at 23K, lOOK and 135K are unswept quartz, the ratio of stable Al-hole centers to associated with the presence of the Al-center. In A1-OH centers is determined by the availability of hydrogen trapped in the growth defect sites. Since these peaks occur at temperatures below the temperature of a crystal oscillator their production causes a negative frequency offset. The magnitude of the radiation-induced offset due to the production of the Al-hole center should match the sum of the heights of these three loss peaks. We have measured the acoustic loss and frequency versus temperature spectra as a function of radiation dose of a number of matching Naswept, unswept. and H-swept AT-cut quartz crystals. As expected, large positive frequency offsets at both the upper and lower turnovers were observed for the Naswept crystals. However, the magnitude of the offset was consistently much less than the change in height of the strong 53K (5MHz) A1-Na loss peak. This smaller offset was caused by a change in "apparent" angle of the crystal that comes about when the A1-Na center is replaced the A1-OH or Al-hole center. King first noted that AT-cut crystals with large A1-Na concentrations behave as if they were cut at a smaller angle than natural or swept crystals. Both the unswept crystals and the H-swept crystals usually showed negative frequency offsets at the turnover temperatures. The offsets of the swept crystals were usually smaller than those of the unswept samples. Only part of the could be explained by summing the heights of the l o s s observed fractional frequency offset at the turnovers peak changes. An additional radiation induced offset was observed at temperatures below 15 K where the the offset does not appear to be related to any acoustic frequency versus temperature curves flatten out. This l o s s peaks; instead, it is caused by shifts in the elastic moduli that take place when a defect is modified. Once this low temperature offset is subtracted from the offset measured at the turnover the by the changes in the acoustic loss peaks. remaining frequency shift matches the value predicted JNTRODUCTION quartz oscillators must be considered in a number of The effects of ionizing radiation on precision aerospace applications. Both transient and steadyof the crystal have been observed following the state frequency offsets and series resistance changes exposure to radiation [ l -1 0 1 . King and Koehler [l]have reviewed the radiation response of quartz with respect to frequency control applications. Norton, Cloeren, and Suter; Suter and Maurer; and Suter have recently reported low-dose frequency offset studies [11,12,13]. Several mechanisms for low-dose effects have been discussed by Flanagan, Leadon, and Shannon [14]. Palkuti and Truong ( ...

show abstract

Evaluation of Mechanisms for Low-Dose Frequency Shifts in Crystal Oscillators

Abstract: A b s t r a c t ___-.

Cited by 10 publications

References 4 publications

Low Dose Rate Proton Irradiation of Quartz Crystal Resonators

Low Dose Rate Proton Irradiation of Quartz Crystal Resonators

The aging of bulk acoustic wave resonators, filters and oscillators

Radiation induced frequency offsets and acoustic loss in AT-cut quartz crystals

Contact Info

Product

Resources

About