X-ray-induced luminescence in crystalline SiO2

Abstract

The x-ray-induced ‘‘blue’’ emission from commercially available, high-quality synthetic quartz has been studied between 80 and 300 K. Three overlapping bands, each having a different quenching temperature, have been experimentally resolved in the as-grown crystals. These bands peak at 440, 425, and 380 nm; their half-widths are 0.64, 0.75, and 0.92 eV; and they thermally quench in the 120–160, 170–210, and 220–270 K regions, respectively. An intense electron irradiation at room temperature or an electrodiffusion (sweep) in a hydrogen atmosphere eliminates the band at 380 nm. Our results suggest that the 380-nm band arises from recombination of an electron with a hole trapped adjacent to an alkali-compensated aluminum ion (i.e., an Al–M+ center). The origins of the bands at 440 and 425 nm remain unknown. As an application of these results, a screening test is described which could assist quality control during selection of quartz bars for use in precision frequency control devices.

The problem of dating quartz 1: Spectroscopic ionoluminescence of dose dependence

“…The process of electron recombination at this centre is complex, and may reflect the development and decay of precursor centres (see McKeever, 1991;Yang and McKeever, 1990 for a discussion). The role of the interstitial alkali ions as charge carriers for the [AlO 4 /M + ]° centres has been confirmed through comparison of 'swept' and 'unswept' quartz luminescence emissions, where the swept quartz has been exposed to intense electron irradiation in a hydrogen atmosphere, causing removal of alkali ions (Alonso et al, 1983;Martini et al, 1995). Swept quartz exhibited no UV emission at 380 nm (3.3 eV), in contrast to an unswept portion of the same sample.…”

“…4), where depletion of the emission is observed, with increasing radiation dose. This dependence of the UV-violet emission to irradiation has also been observed (Botis et al, 2006;Krbetschek and Trautmann, 2000;Rink, 1994), although no precise mechanisms have been determined (Alonso et al, 1983;Halperin and Sucov, 1993;Yang and McKeever, 1990). Exploration of the properties of the extrinsic [AlO 4 /M + ]° defect using CL and ESR, has revealed that the population is highly sensitive to irradiation (Luff and Townsend, 1990;Perny et al, 1992;Weil, 1984).…”

“…Deconvolution indicates that the UV-violet band comprises at least two components at 3.3 and ~3.6 eV and that implantation modifies the relative proportions of these two components. If we accept that the 3.3 eV emission results from [AlO 4 /M + ]° (Alonso et al, 1983;Perny et al, 1992), we can suggest that the 3.6 eV centre is from [AlO 4 ]° and that ion migration during implantation is aw ay from the centre. QzPara and QzPerp exhibit UV emissions at 3.6-3.7 eV before significant implantation.…”

“…McKeever, 1991;Yang and McKeever, 1990), it is widely assumed that the 380 nm (3.3 eV) UV-blue emission is associated with the substitution of Si 4+ with Al 3+ , charge compensated by protons or interstitial alkali ions (Alonso et al, 1983;Perny et al, 1992). This results in the formation of [AlO 4 /M + ]° centres, where the Al 3+ is charge compensated by either Li + , Na + (Perny et al, 1992) or H + Luff and Townsend, 1990).…”

Resolución de enigmas geológicos e históricos utilizando técnicas gemológicas avanzadas: Caso del ópalo noble de Franco Dávila (1772)

“…Sin embargo, también tienen otros centros luminiscentes extrínsecos relacionados con defectos puntuales por inclusión de elementos ajenos, como hierro, manganeso, talio, titanio, uranio, etc. (Alonso et al, 1983;Martini et al, 1995;Krbetschek et al, 1997;Spooner & Questiaux, 2000;Götze et al, 2001). Los mapas de catodoluminiscencia pancromática señalan las anomalías luminiscentes del ópalo y la tomografía computerizada de alta resolución por rayos X (TCRX) resalta diferencias de densidades, pudiendo apreciar la ubicación del cloruro de plata que rellena algunas fisuras y la propia superficie-aire que permite hacer modelos 3D de la pieza destacando muy bien las facetas del tallado (Wellington & Vinegar, 1987;Ketcham & Carlson, 2001).…”