Bias Polarity Switching-Type TlBr X-ray Imager

Katsuyuki Takagi, Kohei Toyoda, Hiroki Kase, Toshiyuki Takagi, Kento Tabata, Tsuyoshi Terao, Hisashi Morii, AKifumi Koike, Toru Aoki, Mitsuhiro Nogami, Keitaro Hitomi

Research output: Contribution to journalArticlepeer-review


This study introduces an X-ray imager that uses TlBr detectors and demonstrates its potential for X-ray imaging applications. Although TlBr detectors are suitable for X-ray imaging applications because of the associated large attenuation coefficients and direct conversion behavior, realizing a flat-panel detector with TlBr involves developing processes. The proposed imager is constructed utilizing a combination of existing technologies; it comprises a plate electrode containing thallium metal to suppress the polarization phenomenon, pixelated silver electrodes with 80 m pitch, and a photon-counting-type readout integrated circuit (ROIC) that can work in the hole as well as electron collection modes. The modulation transfer function (MTF) of the imager is calculated based on the imaging results of an X-ray test chart, and the result corresponds to 180 m sampling. Even though the imager is not designed specifically for TlBr detectors, the measured high-MTF shows the immense potential of TlBr detectors for X-ray imaging applications. In addition, the polarization phenomenon and its recovery effect through bias switching are confirmed to be similar to conventional detectors with large electrodes. The results of this study can motivate the development of flat-panel-detector processes optimized for TlBr detectors.

Original languageEnglish
JournalIEEE Transactions on Nuclear Science
Publication statusAccepted/In press - 2021


  • Detectors
  • Electrodes
  • Image quality
  • Imaging
  • Photonics
  • Semiconductor radiation detector
  • Stacking
  • Thallium bromide
  • X-ray imaging
  • X-ray imaging

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Nuclear Energy and Engineering
  • Electrical and Electronic Engineering


Dive into the research topics of 'Bias Polarity Switching-Type TlBr X-ray Imager'. Together they form a unique fingerprint.

Cite this