Piezoluminescence and thermoluminescence spectral shifts in γ-irradiated KBr and KCl crystals

Abstract

The piezoluminescence emission spectra in γ‐irradiated ultra pure KBr and KCl single crystals are investigated. An isothermal blue shift is observed which increases with the increasing uniaxial pressure. The isobaric thermoluminescence spectra of the same crystals are also measured for comparison. A red shift is observed in this case which increases with the increasing temperature. The results are explained on the basis of the change in the lattice parameter and the band gap energy with pressure and temperature. Glow curve measurements are made to support the proposed explanation.

Progress in triboluminescence-based smart optical sensor system

“…These results differ substantially from those of other reported piezoluminescent materials like gamma-colored alkali halide crystals and rubber [68][69][70] in which the emitted photons normally decreased greatly during repeated cycles of stress [71]. Fig.…”

“…This approach has a benefit over thermography in that it is not limited to evaluating stress distribution under fatigue alone [31,74]. The TL decreased with repetitive loading, similar to other TL materials such as colored alkali halides [63,68]. The TL intensity, however, recovered completely after being irradiated by an UV light (365 nm) at room temperature, indicative of luminescence by a nondestructive deformation of SrAl 2 O 4 :Eu [31].…”

Mechanoluminescence response to the plastic flow of coloured alkali halide crystals

“…(28) and (29). The ML spectra of coloured alkali halide crystals have been found to be similar to their thermoluminescence and afterglow spectra [25][26][27][28]. Such result is expected on the basis of the present investigation.…”

Mechanoluminescence

“…Techniques used for deforming the crystals in ML measurements are: (1) compression (Chandra and Zink, 1980a,b); (2) bending (Alzetta et aI., 1970); (3) stretching (Crasto et al, 1987;Grabec, 1974;Parfeev et al, 1988); (4) loading (Chandra and Elyas, 1979;Atari, 1982;Atari and Ramani, 1986;Eid et al, 1986); (5) piston impact or impulsive (Chandra, 1983); (6) needle impact (Meyer and Polly, 1965); (7) cleaving and cutting (Longchambon, 1925;Batylin et aI., 1992;Dickinson et al, 1990;Meyer et al, 1970b;Chapman and Walton, 1983a,b); (8) laser (Hardy et aI., 1979); (9) shaking (Copty-Wergles et ai., 1990); (10) air-blast (Longchambon, 1925;Sodomka, 1968;Meyer and Obrikat, 1969); (11) scratching (Nakayama et aI., 1992); (12) grinding and milling (Inoue et aI., 1939); and (13) tribo or rubbing (Zhenyi et aI., 1995;Meyer et al, 1970;Keszthelyi and Bard, 1973;Orel et aI., 1989).…”

“…crystal, with the velocity of the moving piston being measured by a velocity transducer. Belyaev and Martyshev (1969), Hardy and Zink (1976), and Chandra (1983) among others used the monochromator-based spectrometer for measuring ML spectra, and Walton and Botos (1978) and Atari and Ramani (1986) used an image-intensifier spectrometer.…”