Electron Spin-Echo Measurements of E 1 ′ Centers in Crystalline Quartz

A standard spin-echo technique has been employed to determine the electronic phase-memory time of radiation-produced $E_{1}^{\ensuremath{'}}$ centers in crystalline quartz at 4.2, 77, and 300\ifmmode^\circ\else\textdegree\fi{}K. The phase-memory time was found to be independent of temperature.