Journal of the Optical Society of Korea

Optical Society of Korea (한국광학회)
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A TiO2-Coated Reflective Layer Enhances the Sensitivity of a CsI:Tl Scintillator for X-ray Imaging Sensors

  • Kim, Youngju (Iksan Radiation Imaging Technology Center) ;
  • Kim, Byoungwook (Iksan Radiation Imaging Technology Center) ;
  • Kwon, Youngman (Iksan Radiation Imaging Technology Center) ;
  • Kim, Jongyul (Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology) ;
  • Kim, MyungSoo (Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology) ;
  • Cho, Gyuseong (Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology) ;
  • Jun, Hong Young (BK21plus Program and Department of Smart Life-Care Convergence, Wonkwang University) ;
  • Thap, Tharoeun (BK21plus Program and Department of Smart Life-Care Convergence, Wonkwang University) ;
  • Lee, Jinseok (BK21plus Program and Department of Smart Life-Care Convergence, Wonkwang University) ;
  • Yoon, Kwon-Ha (BK21plus Program and Department of Smart Life-Care Convergence, Wonkwang University)
  • Received : 2014.05.19
  • Accepted : 2014.05.12
  • Published : 2014.06.25
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Abstract

Columnar-structured cesium iodide (CsI) scintillators doped with thallium (Tl) are frequently used as x-ray converters in medical and industrial imaging. In this study we investigated the imaging characteristics of CsI:Tl films with various reflective layers-aluminum (Al), chromium (Cr), and titanium dioxide ($TiO_2$) powder-coated on glass substrates. We used two effusion-cell sources in a thermal evaporator system to fabricate CsI:Tl films on substrates. The scintillators were observed via scanning electron microscopy (SEM), and scintillation characteristics were evaluated on the basis of the emission spectrum, light output, light response to x-ray dose, modulation transfer function (MTF), and x-ray images. Compared to control films without a reflective layer, CsI:Tl films with reflective layers showed better sensitivity and light collection efficiency, and the film with a $TiO_2$ reflective layer showed the best properties.

Keywords

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