Radiation Effects in Synthetic Quartz: The Role of Electrodiffusion and Radiation-Induced Mobility of Interstitial Ions

Interstitial ions, both alkalis and hydrogen, have been shown to play a crucial role in the radiation response of high-quality commercially-available quartz. Electron spin resonance (ESR), infrared absorption (IR), and acoustic loss (Q-1) measurements have been made on various samples, swept and unswept, cut from Sawyer and Toyo material. These measurements have shown that the number and nature of irradiation-induced defects depend strongly on the irradiation temperature and previous sweeping treatments. In unswept samples, interstitial alkalis are initially trapped adjacent to substitutional Al3+ ions but become mobile if the irradiation temperature is above 200 K. In swept samples, the interstitial alkalis are replaced by hydrogen, in the form of OH- molecules, and irradiation at temperatures as low as 77 K causes the hydrogen to become mobile. The substantial difference in temperature for onset of the radiation-induced mobility of the alkali and hydrogen interstitial ions forms the basis of a sensitive method for testing completeness of the sweeping process.