TL Characteristics of CsI Single Crystal Scintillators and their Growth Conditions

CsI 단결정 섬광체의 열형광특성과 육성조건

  • Doh, S.H. (Dept. of Physics, Pukyong Nat'l Univ.) ;
  • Lee, W.G. (Dept. of Physics, Pukyong Nat'l Univ.) ;
  • Hong, S.Y. (Dept. of Physics, Pukyong Nat'l Univ.) ;
  • Bang, S.W. (Dept. of Physics, Pukyong Nat'l Univ.) ;
  • Kang, K.J. (Dept. of Physics, Pukyong Nat'l Univ.) ;
  • Kim, D.S. (Dept. of Physics, Education, Taegu Univ.) ;
  • Kim, W. (Dept. of Physics, Kyungpook Nat'l Univ.) ;
  • Kang, H.D. (Dept. of Physics, Kyungpook Nat'l Univ.)
  • Published : 1998.07.31

Abstract

Changes in transmission and thermoluminescent characteristics were used in order to find out the optimum growth condition of CsI single crystal scintillators which were made relatively defect-free using Czochralski method. Impurity distribution in the crystals and the intensity and number of thermoluminescent glow peaks decreased as the process of crystallization was repeated. The direction of crystal growth turned out to be (110), the crystal structure of grown CsI was bee, and its lattice constant was found to be $4.568{\AA}$. The activation energy (trap depths) of CsI:3rd was 0.45 eV and its frequency factor was $5.18{\times}10^5\;sec^{-1}$.

Czochralski 방법을 사용하여 격자결함이 적은 CsI 단결정 섬광체를 육성하기 위한 최적육성조건을 구하기 위하여 광투과율의 변화와 열형광특성을 이용하였다. 결정화과정을 반복할수록 불필요한 불순물 분포와 열형광강도 및 glow 피이크의 수가 감소하였다. 결정성장방향은 (110)이었고, 육성한 CsI의 결정구조는 체심입방체이었다. 그리고 격자상수는 $4.568{\AA}$ 임을 확인할 수 있었다. CsI:3rd의 활성화 에너지(trap깊이)는 약 0.45 eV 이었고, 주파수인자는 $5.18{\times}10^5\;sec^{-1}$이었다.

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