Temperature characteristics of the TlBr radiation detectors

Abstract

TlBr crystal is very promising as a material for radiation detectors, which operate at room temperature. Especially, the TlBr detector is predicted to be excellent in the energy range from 100 keV to 1 MeV, but fabrication of the TlBr radiation detector is still in its rudimentary stage. In this paper, the response characteristics (FWHM (Full Width at Half Maximum) and mobility) of the TlBr radiation detector were discussed as a function of the detector temperature. The range of the temperature was from 220 K to 390 K. Gamma ray detectors were fabricated from the TlBr crystals grown by TMZ (Traveling Molten Zone) method, and the response characteristics were measured as a function of the temperature of the detector. As the experimental results, the followings were illustrated: (1) spectra characteristics of the alpha rays; (2) the variation of FWMH; (3) the change of resistivity; and (4) the mobility and FWHM. The TlBr detector showed the best response characteristics at about 330 K. At the temperature of 330 K or above, the mobility showed rapid decrease and the FWHM worsened.

TlBr結晶は室温で作動する放射線検出器向けの材料として非常に有望である。特に100keVから1MeVのエネルギー範囲で優れていると予想されるが、その開発は初歩的な段階にある。本論文では、検出器温度の関数としてTlBr放射線検出器の応答特性(半値幅および移動度)を論じた。温度範囲は220Kから390Kであった。ガンマ線検出器はTMZ(移動溶融帯)法によって成長させた結晶から製作し、検出器の温度関数として応答特性を測定した。実験結果として以下のグラフで図示した。アルファ線のスペクトル特性、FWHMの変動、比抵抗の変化、移動度とFWHM。TlBr検出器はおよそ330Kで最良の応答特性を示した。温度330Kまたはそれ以上で移動度は急速な低下を示し、FWHMは悪化した。