A response matrix determined with a coincidence-based acquisition for correction of charge sharing spectral distortions in energy-resolved photon counting detectors
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| Main Authors: | , , , , , , , , , |
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| Format: | Preprint |
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2025
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| _version_ | 1866911126668705792 |
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| author | Monaco, Vincenzo Brombal, Luca Delogu, Pasquale Feruglio, Alessandro Fiorini, Massimiliano Longo, Renata Marchetti, Luca Poli, Anna Maria Rigon, Luigi Rosso, Valeria |
| author_facet | Monaco, Vincenzo Brombal, Luca Delogu, Pasquale Feruglio, Alessandro Fiorini, Massimiliano Longo, Renata Marchetti, Luca Poli, Anna Maria Rigon, Luigi Rosso, Valeria |
| contents | A model-independent method is proposed to characterize and correct charge sharing spectral distortions in energy-resolved X-ray acquisitions with pixellated photon-counting detectors. The technique is based on the determination of a coincidence-based response matrix (CBRM) through a preliminary calibration with a uniform irradiation and an arbitrary polychromatic spectrum. The calibration requires the collection of the number of coincidences between a reference pixel and its neighbours for different combinations of energy bins, in order to calculate a set of charge sharing probabilities which are independent of the input spectrum. A detector response matrix is determined, which can afterwards be applied to correct other spectra acquired with the same detector and a conventional multi-comparator electronics, without introducing penalties in terms of processing time. The technique was validated with Geant4 simulations of a 1 mm thick CdTe detector and with data collected with a pixel hybrid detector made of a 300 um thick silicon sensor coupled to a Timepix4 ASIC chip. The differences between the reconstructed spectra and reference distributions of an ideal detector or a 3x3 offline clustering algorithm were evaluated in terms of mean absolute percentage errors. It is demonstrated that the response matrix can restore the spectral information with a performance close to standard clustering algorithms and is less affected by noise artifacts than analog charge summing techniques. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2508_05730 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | A response matrix determined with a coincidence-based acquisition for correction of charge sharing spectral distortions in energy-resolved photon counting detectors Monaco, Vincenzo Brombal, Luca Delogu, Pasquale Feruglio, Alessandro Fiorini, Massimiliano Longo, Renata Marchetti, Luca Poli, Anna Maria Rigon, Luigi Rosso, Valeria Instrumentation and Detectors Medical Physics A model-independent method is proposed to characterize and correct charge sharing spectral distortions in energy-resolved X-ray acquisitions with pixellated photon-counting detectors. The technique is based on the determination of a coincidence-based response matrix (CBRM) through a preliminary calibration with a uniform irradiation and an arbitrary polychromatic spectrum. The calibration requires the collection of the number of coincidences between a reference pixel and its neighbours for different combinations of energy bins, in order to calculate a set of charge sharing probabilities which are independent of the input spectrum. A detector response matrix is determined, which can afterwards be applied to correct other spectra acquired with the same detector and a conventional multi-comparator electronics, without introducing penalties in terms of processing time. The technique was validated with Geant4 simulations of a 1 mm thick CdTe detector and with data collected with a pixel hybrid detector made of a 300 um thick silicon sensor coupled to a Timepix4 ASIC chip. The differences between the reconstructed spectra and reference distributions of an ideal detector or a 3x3 offline clustering algorithm were evaluated in terms of mean absolute percentage errors. It is demonstrated that the response matrix can restore the spectral information with a performance close to standard clustering algorithms and is less affected by noise artifacts than analog charge summing techniques. |
| title | A response matrix determined with a coincidence-based acquisition for correction of charge sharing spectral distortions in energy-resolved photon counting detectors |
| topic | Instrumentation and Detectors Medical Physics |
| url | https://arxiv.org/abs/2508.05730 |