Abstract

The photoluminescence (PL), radioluminescence (RL) and thermoluminescence (TL), excited in natural Norwegian quartz crystals by monochromatic uv light, beta and X-rays, were studied. Excitation and emission spectra were measured and the dependence of the intensities and the spectral composition of the emission on irradiation temperature as well as on thermal pre-treatment was investigated. The PL excitation spectra in the vacuum uv region between 115-185 nm shows a main maximum at 127 nm. A strong excitation maximum of the TL has recently been recorded at the same wavelength and the TL intensities were found to be comparable to those induced by a 10 m Ci ⁹⁰Sr beta source.⁽¹⁾ The 127 nm excitation maximum coincides with the long-wavelength tail of an exciton peak, previously recorded in the reflectance spectrum of quartz.⁽²⁾ However, the PL and TL could also be excited with photons of energies lower than the absorption edge. The PL, as well as the RL and TL emissions showed a broad emission band centered at 440 nm (with a half­width of about 0.80 ev), which was dominant at 80K. Another broad main emission band appeared near 370 nm and could be resolved under certain conditions in 355 and 380 nm bands (with half-widths of 0.50 and 0.42 ev). Additional weaker bands were recorded at about 340 and 520 nm. The relative intensities of these bands depend markedly on the temperature of excitation as well as on thermal pre-treatment. The 440 nm band decreases sharply with increasing temperature near 200K, which resembles the temperature dependence of a STE luminescence. This band may possibly be due to radiative decay of a self trapped exciton. The 355 and 380 nm bands showed a different temperature dependence. Emission bands near 380 nm have previously been reported by various authors.^(e.g.3,4) Alonso et al. ascribed the broad 380 nm band, recorded in the X-luminescence,to a recombination of electrons with holes, trapped at an adjacent Al-M⁺ center.⁽⁴⁾ The fact that the samp emission bands appeared in the uv excited PL as in the X and beta excited RL and TL, indicates that the emission is due to the same luminescence centers.

© 1984 Optical Society of America