COUNTERFEIT E-1' SIGNAL IN QUARTZ

A distinct ESR (electron spin resonance) signal was found to overlap t he E-1' centre signal in natural quartz irradiated by gamma-rays. Its g-value is identical to the signal of the E-1' centre and its intensit y begins to saturate below a microwave power of 0.4 mW, as does that o f the E-1' centre. The shape of this signal shows one peak, whereas th e ''real'' E-1' centre signal is almost axial, having two peaks. The o verlapping signal was found to be very unstable and its half life was estimated to be 28 years at 15 degrees C (mean life of 40 years). We n amed it the ''counterfeit E-1' signal''. We show the necessity of exam ining the signal shape and the thermal stability of the supposed E-1' signal observed in natural quartz irradiated by gamma-rays. (C) 1997 E lsevier Science Ltd.