ÚTEFČVUT Ústav technické a experimentální fyziky ČVUT v PrazeInstitute of Experimental and Applied Physics, CTU in Prague

Precise energy calibration of pixel detector working in time-over-threshold mode

NázevTitle
Precise energy calibration of pixel detector working in time-over-threshold modePrecise energy calibration of pixel detector working in time-over-threshold mode
Druh výsledkuResult type
Článek v časopiseJournal article
AutořiAuthors
J. Jakůbek
Klíčová slovaKeywords
pixel detector, X-ray radiography, Material recognition
KonferenceConference
13th International Workshop on Radiation Imaging Detectors (Villingen and Zurich, Switzerland, 2011-07-03)
DOIDOI
10.1016/j.nima.2010.06.183
Časopis / citaceJournal / citation
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 633, S262-S266 (2011) · ISSN 0168-9002
RokYear
2011
JazykLanguage
eng
ZáznamyRecords
ProjektProject
Příprava, modifikace a charakterizace materiálů energetickým zářenímPreparation, Modification and Characterization of Materials by Energetic Radiation; Využití radionuklidů a ionizujícího zářeníApplication of radionuclides and ionising radiation
CitovánoCited by
106 (INSPIRE-HEP)
2011: 32012: 32013: 52014: 22015: 102016: 92017: 42018: 112019: 32020: 102021: 122022: 42023: 52024: 112025: 92026: 5
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AbstraktAbstract

The semiconductor pixel detector Timepix (256 x 256 pixels with pitch of 55 mu m) is a successor of the Medipix2 device. Each Timepix pixel can be independently operated in one of three possible modes: (1) counting of the detected particles; (2) measurement of the particle energy; and (3) measurement of the time of interaction. The energy measurement in the second mode is performed via the determination of the "time-over-threshold" (TOT). The energy measurement with the Timepix detector in TOT mode requires knowledge of the energy calibration of each pixel of the matrix. Such calibration is very nonlinear in the low energy range and can be described by a surrogate function depending on four parameters. The determination of all these parameters can be performed by measurement and evaluation of the response of each pixel in at least four calibration points. The procedure is extremely demanding: it requires the analysis of at least 250 thousand spectra and the performance of 330 thousand least-squares fits. In this article, it is demonstrated that even better result can be achieved with only two or three calibration points halving the number of least-squares fits needed. The method is based on precise analysis of the shape of spectral peaks. The article also discusses the performance of energy calibrated device for spectrometry of heavy charged particles.

The semiconductor pixel detector Timepix (256 x 256 pixels with pitch of 55 mu m) is a successor of the Medipix2 device. Each Timepix pixel can be independently operated in one of three possible modes: (1) counting of the detected particles; (2) measurement of the particle energy; and (3) measurement of the time of interaction. The energy measurement in the second mode is performed via the determination of the "time-over-threshold" (TOT). The energy measurement with the Timepix detector in TOT mode requires knowledge of the energy calibration of each pixel of the matrix. Such calibration is very nonlinear in the low energy range and can be described by a surrogate function depending on four parameters. The determination of all these parameters can be performed by measurement and evaluation of the response of each pixel in at least four calibration points. The procedure is extremely demanding: it requires the analysis of at least 250 thousand spectra and the performance of 330 thousand least-squares fits. In this article, it is demonstrated that even better result can be achieved with only two or three calibration points halving the number of least-squares fits needed. The method is based on precise analysis of the shape of spectral peaks. The article also discusses the performance of energy calibrated device for spectrometry of heavy charged particles.

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