γ-ray irradiation effects in quartz, (2)

A study was made on irradiation effects of Co-60 γ ray on crystalline quartz by measuring properties of the mechanical oscillation, the optical absorption, and ESR. Changes of the frequency and the internal friction were measured using AT-cut oscillator elements cut from three different kinds of quartz. An initial decrement of the frequency up to 107 R is considered to be responsible for the sup(Al)Asub(+) defect center which consists of an aluminum impurity atom at a Si site with an unpaired electron. The ESR signal and the optical absorption band due to the sup(Al)Asub(+) defect center were also observed in irradiated samples. The decrement of the frequency at higher doses seems to be due to defect centers associated with another kind of impurity, which also causes increase in the internal friction. (auth.)