Performance assessment of CsI(Tl) screens on various substrates for X-ray imaging

Performance assessment of CsI(Tl) screens on various substrates for X-ray imaging


FENG Zhao-Dong, JIANG Peng, ZHANG Hong-Kai, ZHAO Bo-Zhen, QIN Xiu-Bo, WEI Cun-Feng, LIU Yu, WEI Long. "Performance assessment of CsI(Tl) screens on various substrates for X-ray imaging". Chinese Physics C, [Submitted]. 

  • CsI(Tl) scintillation screen
  • substrate
  • imaging performance evaluation 


The performance of CsI(Tl) scintillation screens in X-ray imaging can be optimized by using different substrates like graphite, silver-film coated SiO2, and fiber optic plate to control optical features like light output, spatial resolution, and signal-to-noise ratio.


This article, submitted to 'Chinese Physics C', examines the impact of different substrates on the performance of thallium-doped cesium iodide (CsI(Tl)) screens used in X-ray imaging.
The authors used four substrates: fused silica (SiO2), silver-film coated SiO2, graphite (C), and fiber optic plate (FOP). They evaluated the imaging performance of each screen using metrics such as relative light output (RLO), modulation transfer function (MTF), normalized noise power spectrum (NNPS), and noise equivalent quanta (NEQ).

Key Findings:

  • Graphite (C-Subs): While producing the dimmest images, the C-Subs provided the highest spatial resolution (MTF) and a good signal-to-noise ratio (NEQ), likely due to its ability to absorb backward scintillation photons.
  • Silver-coated SiO2 (Ag-SiO2-Subs): The silver film enhanced light output compared to bare SiO2 by reflecting backward scattered photons.
  • SiO2 (SiO2-Subs): Screens on SiO2, with or without silver coating, exhibited lower spatial resolution and a worse signal-to-noise ratio compared to FOP and C-Subs.
  • Fiber Optic Plate (FOP-Subs): FOP-based screens yielded the brightest images and demonstrated the best NNPS performance and high NEQ due to the fiber optic's ability to efficiently guide scintillation photons. However, they had the lowest spatial resolution.

The study concluded that by choosing appropriate substrates, one could tailor the performance of CsI(Tl) screens to meet the specific needs of different X-ray imaging applications

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