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Purpose <p>Pixelated CZT detectors in imaging applications usually suffer from severe low-energy tails due to poor small-pixel effects at large pixel size to thickness ratios. This study proposes a weighting potential compensation (WPC) technique to improve spectral performance without complex hardware modifications.</p> Methods <p>A WPC technique is proposed, utilizing subtraction readout between adjacent pixels with adjustable relative gain, emulating coplanar grid principles. A comprehensive simulation platform combining Geant4, finite element analysis, and ROOT was developed. This technique was validated and applied to a 5 mm thick SPECT detector with 2.46 mm pixel pitch.</p> Results <p>The WPC technique reshapes the effective weighting potential, compensating for electron trapping and enhancing charge collection uniformity. At optimal gain of 1.2-1.3, energy resolution for 140 keV gamma rays improved from 4.18% to 3.23%, and the peak-to-total ratio increased by 25%. Charge collection efficiency maps confirmed reduced low-tail-forming regions.</p> Conclusion <p>The WPC technique enhances spectral performance in pixelated CZT detectors with large p/L ratios using simple subtraction circuitry, enabling better energy resolution and photopeak efficiency for imaging applications like SPECT. Future work will integrate the subtraction circuitry into imaging hardware.</p>

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Improving pixelated CZT detector performance using the weighting potential compensation technique

  • 期刊论文

  • 发表日期：

    2025年7月24日

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  • Qianying Zhang,
  • Yang Sui,
  • Jianqiang Fu,
  • Xiangyin Li,
  • Yuchao Yan

摘要

Purpose

Pixelated CZT detectors in imaging applications usually suffer from severe low-energy tails due to poor small-pixel effects at large pixel size to thickness ratios. This study proposes a weighting potential compensation (WPC) technique to improve spectral performance without complex hardware modifications.

Methods

A WPC technique is proposed, utilizing subtraction readout between adjacent pixels with adjustable relative gain, emulating coplanar grid principles. A comprehensive simulation platform combining Geant4, finite element analysis, and ROOT was developed. This technique was validated and applied to a 5 mm thick SPECT detector with 2.46 mm pixel pitch.

Results

The WPC technique reshapes the effective weighting potential, compensating for electron trapping and enhancing charge collection uniformity. At optimal gain of 1.2-1.3, energy resolution for 140 keV gamma rays improved from 4.18% to 3.23%, and the peak-to-total ratio increased by 25%. Charge collection efficiency maps confirmed reduced low-tail-forming regions.

Conclusion

The WPC technique enhances spectral performance in pixelated CZT detectors with large p/L ratios using simple subtraction circuitry, enabling better energy resolution and photopeak efficiency for imaging applications like SPECT. Future work will integrate the subtraction circuitry into imaging hardware.