LaBr₃:Ce and silicon photomultipliers

LaBr₃:Ce and silicon photomultipliers: Towards the optimal scintillating photon-counting detector

van der Sar, S.J. (TU Delft RST/Medical Physics & Technology)
Leibold, D. (TU Delft RST/Medical Physics & Technology)
Brunner, Stefan E. (Broadcom Inc., Regensburg)
Schaart, D.R. (TU Delft RST/Medical Physics & Technology; Holland Particle Therapy Centre)

Stayman, Joseph Webster (editor)

2022

We investigate fast silicon photomultiplier (SiPM)-based scintillation detectors for X-ray photon-counting applications, e.g., photon-counting computed tomography (CT). Such detectors may be an alternative to CdTe/CdZnTe (CZT) and Si detectors, which face challenges related to availability and cost-effective growth of detector-grade material, and detection efficiency, respectively. Here, we experimentally study energy response and count rate performance of a 1 mm × 1 mm single-pixel detector consisting of the readily available LaBr3:Ce scintillator and an ultrafast SiPM. We used three radio-isotopes and an X-ray tube for the experiments. Raw detector signals were processed by a second-order low-pass filter with a cut-off frequency f_c equal to 25 MHz or 100 MHz. The detector pulse height was shown to be proportional to photon energy. We measured FWHM energy resolutions of 19.5% (f_c=25 MHz) and 21.5% (f_c=100 MHz) at 60 keV. The measured X-ray tube spectra showed signs of the expected features of such spectra. The best count rate performance was achieved using f_c=100 MHz. In case of paralyzable-like counting and a 30 keV counting threshold, the maximum observed count rate (OCR) was 10.5 Mcps/pixel. For nonparalyzable-like counting and the same threshold, the OCR appeared to approach an asymptotic value greater than 20 Mcps/pixel. These numbers are close to those of CdTe/CZT detectors highly optimized for photon-counting CT. In conclusion, we show promising spectral X-ray photon-counting performance of an LaBr3:Ce scintillation detector with SiPM readout. Depending on the application-specific requirements, miniaturization of the pixel size may be necessary, for which we discuss potential dose-efficient implementations.

Count rate performance
energy response
scintillator
silicon photomultiplier
X-ray photon-counting

http://resolver.tudelft.nl/uuid:68b59f72-aed3-4ac6-a236-9f32cb4ab765

https://doi.org/10.1117/12.2646519

SPIE

9781510656697

7th International Conference on Image Formation in X-Ray Computed Tomography

7th International Conference on Image Formation in X-Ray Computed Tomography, 2022-06-12 → 2022-06-16, Virtual, Online

Proceedings of SPIE - The International Society for Optical Engineering, 0277-786X, 12304

Institutional Repository

conference paper

© 2022 S.J. van der Sar, D. Leibold, Stefan E. Brunner, D.R. Schaart