Photoluminescence and scintillation of TlBr crystals at low temperatures

Abstract

The photoluminescence and X-ray-induced radioluminescence properties of TlBr crystals were analyzed. We compared the samples cut from two parts of the crystal that are empirically known to be appropriate and inappropriate for semiconductor detectors. In the X-ray-induced radioluminescence spectra, two bands were observed at 490 and 650 nm for both the samples. We observed an additional band at 560 nm only for the inappropriate part of the crystal. We observed an emission band at 520 nm in the photoluminescence spectra of both the samples and attributed this to some defects near the surface on which photoexcitation occurs. Interestingly, an emission band at 560 nm appeared after thermal cycle from room temperature to 5 K and back to room temperature. Assuming that the thermal cycle introduced some distortions in the sample, the emission band at 560 nm could be related to lattice defects, such as dislocation, that are relevant to distortion.

Transient Absorption Spectroscopy of TlBr Crystals Using Pulsed Electron Beams

“…Besides, the decay time scale indicates that the hole traps hinder the hole transport. The difference between transient absorption behaviors on the pico-and nanosecond scales of the appropriate and inappropriate crystals was negligible, which suggests that the electron and hole trapping behaviors of the crystals are almost similar, although the crystals exhibited significant differences in their photoluminescence and radioluminescence spectra in our previous paper, (13) in which it is strongly suggested that the concentration of dislocation-type defects was significantly different between the two crystals. These results indicate that the two crystals were similar from the viewpoint of the concentration of point defects, whereas they are quite different in the dislocation concentration.…”

“…The crystals were obtained from the same portion as those used in our previous study. (13) The thicknesses of the appropriate and inappropriate crystals were 0.611 and 0.616 mm, respectively. The details of the crystal growth have been described in a previous paper.…”

“…(9)(10)(11)(12) Similarly, photoluminescence, cathodoluminescence, and scintillation spectroscopies with steady-state and time-resolved measurements at different temperatures have revealed lattice imperfections such as point defects and dislocations. (13)(14)(15)(16) In this study, we employed transient absorption spectroscopy to characterize TlBr crystals. This is a powerful technique to analyze the dynamics of electron-hole pairs.…”

Characterization of coincidence time resolutions of TlBr x Cl1−x crystals as Cherenkov radiators

“…TlBr has also been studied for X-ray imaging. 25) Wavelength-resolved neutron imaging, 26) photoluminescence and X-ray-induced radioluminescence analyzes 27) have been performed to characterize TlBr crystals. One of the attractive applications of TlBr detectors is positron emission tomography in which the detectors require good detection efficiency and timing performance.…”

Cryogenic Scintillation Performance of Cs4PbI6 Perovskite Single Crystals

“…Scintillators, which have the capacity of converting ionizing radiation into visible photons, are widely used in various applications, including medical diagnostics, safety inspection, and scientific research. − Currently, the application of the scintillation detectors at cryogenic temperature has drawn tremendous attention because of the enthusiasm in dark matter searches. − The demand for cryogenic scintillation detection has motivated the investigation of the cryogenic performances of scintillators. Conventional cryogenic scintillators, such as cadmium tungstate and cadmium molybdate, suffer from the limitations of their intrinsic radioactivity, which pose a major challenge for their application in dark matter searches. ,, Therefore, with the application of scintillation detectors in extreme conditions increasing, it is urgent to develop a novel scintillator and characterize the corresponding scintillation properties at cryogenic temperatures. − …”