Amorphous selenium (a-Se) is a glass-former capable of deposition at high rates by thermal evaporation over a large area. It was chosen as a direct conversion material due to its appealing properties for imaging in both low and high X-ray energy ranges (<30 keV and <30 keV, respectively). It has a bandgap of 2.2 eV and can achieve high photodetection efficiency at short wavelengths less than 400 nm which makes it appealing for indirect conversion detectors. The integration of a-Se with readout integrated circuits started with thin-film transistors for digital flat panel X-ray detectors. With increasing applications in life science, biomedical imaging, X-ray imaging, high energy physics, and industrial imaging that require high spatial resolution, the integration of a-Se and CMOS is one direct way to improve the high-contrast visualization and high-frequency response. Over the past decade, significant improvements in a-Se/CMOS technologies have been achieved with improvements to modulation transfer function and detective quantum efficiency. We summarize recent advances in integrating and photon-counting detectors based on a-Se coupled with CMOS readout and discuss some of the shortcomings in the detector structure, such as low charge conversion efficiency at low electric field and high dark current at high electric field. Different pixel architectures and their performance will be highlighted.
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The CeBrA demonstrator for particle-γ coincidence experiments at the FSU Super-Enge Split-Pole Spectrograph
We report on a highly selective experimental setup for particle-γ coincidence experiments at the Super-Enge Split-Pole Spectrograph (SE-SPS) of the John D. Fox Superconducting Linear Accelerator Laboratory at Florida State University (FSU) using fast CeBr3 scintillators for γ-ray detection. Specifically, we report on the results of characterization tests for the first five CeBr3 scintillation detectors of the CeBr3 Array (CeBrA) with respect to energy resolution and timing characteristics. We also present results from the first particle-γ coincidence experiments successfully performed with the CeBrA demonstrator and the FSU SE-SPS. We show that with the new setup, γ-decay branching ratios and particle-γ angular correlations can be measured very selectively using narrow excitation energy gates, which are possible thanks to the excellent particle energy resolution of the SE-SPS. In addition, we highlight that nuclear level lifetimes in the nanoseconds regime can be determined by measuring the time difference between particle detection with the SE-SPS focal-plane scintillator and γ-ray detection with the fast CeBrA detectors. Selective excitation energy gates with the SE-SPS exclude any feeding contributions to these lifetimes.
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- PAR ID:
- 10521812
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- arxiv.org
- Date Published:
- Journal Name:
- Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
- Volume:
- 1058
- Issue:
- C
- ISSN:
- 0168-9002
- Page Range / eLocation ID:
- 168827
- Subject(s) / Keyword(s):
- Low-energy nuclear physics, γ-ray detection, CeBr3 scintillators, fast timing, magnetic spectrographs, particle-γ coincidences
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1016/j.nima.2023.168827
