Radiation-induced transient acoustic loss in quartz crystals

When exposed to pulsed ionizing radiation, quartz oscillator crystals can exhibit transient acoustic losses (a decrease in Q) and transient frequency shifts. Although these changes are usually most pronounced in unswept quartz, they have also been seen in swept quartz. We have directly measured the transient acoustic loss in both synthetic and natural quartz. The synthetic quartz samples included hydrogen and lithium swept units. Irradiations were accomplished at REBA, a flash x-ray facility at Sandia Laboratories. Log decrement acoustic loss measurements were made over the 110–400 K temperature range and show a time dependence similar to a t−1/2 behavior characteristic of one-dimensional diffusion. The transient loss showed a broad temperature dependence ascribed to alkali ions moving along the Z-axis channels. Peaks at 360 and 380 K in the transient loss temperature spectra are thought to be due to an unstable defect which momentarily traps the alkali ion.