Time resolution measurement of avalanche counters using digital signal processing technique

Nakhostin, M.; Oishi, T.; Baba, Mamoru

doi:10.1016/j.radmeas.2008.05.016

Cited by 10 publications

(4 citation statements)

References 17 publications

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“…The coincidence time spectra were acquired by calculating the difference between the arrival-times of the pulses from the two detectors placed at the same geometry as the analogue measurement. To determine the arrival time of the pulses, a range of digital timing methods have been reported in the literature [17][18][19][20][21], among which the digital Constant-Fraction Discrimination (CFD) method was chosen due to its widespread use, reliability and simple implementation [18,21]. The digital CFD searches for the maximum digitized value of the pulses and sets a threshold which is a fraction of the pulse maximum value.…”

Section: Timing Measurementsmentioning

confidence: 99%

Digital processing of signals from LaBr₃:Ce scintillation detectors

2014

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In this paper, we report on the results of digital signal processing of LaBr 3 (Ce) detectors. The photomultiplier (PMT) output signals from two cylindrical LaBr 3 (Ce) detectors (1.5 diameter and 2 tall) were directly digitized with an ultrafast digitizer (sampling rate up to 4 GSample/s and 10-bits resolution) and the energy and timing information were extracted through offline analysis of the pulses. It is shown that at high sampling rates (4 GS/s) a simple integration of pulses is sufficient to reproduce the analogue energy resolution of the detectors (3.5% at 662 keV energy) and by employing a digital version of constant-fraction discrimination (CFD) timing a time resolution of 240 ps (FWHM) is achieved at the energy lines of 60 Co. The effects of pulse sampling rate were studied, indicating a degradation of the performance of the detectors with reducing the pulse sampling rate. In particular, it was found that at sampling rates below 1 GS/s, the digital timing can be limited by the aliasing error. By using an anti-aliasing filter, a time resolution of 375 ps (FWHM) and an energy resolution of 3.5% at 662 keV were achieved with a sampling rate of 500 MS/s.

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Section: Timing Measurementsmentioning

confidence: 99%

Digital processing of signals from LaBr₃:Ce scintillation detectors

2014

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“…The pulse is then analysed to determine when it initially crosses the threshold and the crossing time is taken as the arrival-time of the pulse. The arrival-time of the pulse is linearly interpolated if it falls between the signal samples (Nakhostin et al 2008). In regard to the LaBr 3 (Ce) detector, the pulse arrival-time is marked directly with the digital CFD.…”

Section: Digital Pulse Processing Methodsmentioning

confidence: 99%

Optimizing timing performance of CdTe detectors for PET

Nakhostin¹

2017

Phys. Med. Biol.

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Despite several attractive properties, the poor timing performance of compound semiconductor detectors such as CdTe and CdZnTe has hindered their use in commercial PET imaging systems. The standard method of pulse timing with such detectors is to employ a constant-fraction discriminator at the output of a timing filter which is fed by the pulses from a charge-sensitive preamplifier. The method has led to a time resolution of about 10 ns at full-width at half-maximum (FWHM) with 1 mm thick CdTe detectors. This paper presents a detailed investigation on the parameters limiting the timing performance of Ohmic contact planar CdTe detectors with the standard pulse timing method. The jitter and time-walk errors are studied through simulation and experimental measurements and it is revealed that the best timing results obtained with the standard timing method suffer from a significant loss of coincidence events (~50%). In order to improve the performance of the detectors with full detection efficiency, a new digital pulse timing method based on a simple pattern recognition technique was developed. A time resolution of 3.29 ± 0.10 ns (FWHM) in the energy range of 300-650 keV was achieved with an Ohmic contact planar CdTe detector (5 × 5 × 1 mm). The digital pulse processing method was also used to correct for the charge-trapping effect and an improvement in the energy resolution from 4.83 ± 0.66% to 2.780 ± 0.002% (FWHM) at 511 keV was achieved. Further improvement of time resolution through a moderate cooling of the detector and the application of the method to other detector structures are also discussed.

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“…1. First, a digital discriminator, such as leading-edge or a constant-fraction discrimination (CFD) [21], marks the start of the pulse. Then, the vector x is formed by taking the pulse samples that lie in a time window starting from the pulse's starttime.…”

Section: B the Psd Algorithmmentioning

confidence: 99%

A General-Purpose Digital Pulse Shape Discrimination Algorithm

Nakhostin

2019

IEEE Trans. Nucl. Sci.

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Digital pulse-shape discrimination (PSD) systems are widely used to extract various kinds of information from the shape of output pulses of radiation detectors. Such systems replace the traditional analog PSD circuits with numerical algorithms running on a digital processor which makes them more flexible for implementing various PSD methods. However, the available digital PSD algorithms have been generally tailored to the characteristics of the concerned detectors which limits their general use. Here, for the purpose of building a general-purpose digital PSD module, we present a PSD algorithm that with minimum alterations can be used with a wide range of radiation detectors. Our approach is based on using the cosine similarity measure to quantify the variations in the shape of detectors' pulses with respect to the shape of a unit step pulse. The method is described in details, and the results of the test experiments with different types of radiation detectors, including a boron tetrafluoride (BF3) proportional counter, a liquid scintillation detector, and a high purity germanium (HPGe) detector are shown. The performance of the algorithm is also compared to that of the common rise-time discrimination method.

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Time resolution measurement of avalanche counters using digital signal processing technique

Cited by 10 publications

References 17 publications

Digital processing of signals from LaBr₃:Ce scintillation detectors

Digital processing of signals from LaBr₃:Ce scintillation detectors

Optimizing timing performance of CdTe detectors for PET

A General-Purpose Digital Pulse Shape Discrimination Algorithm

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Time resolution measurement of avalanche counters using digital signal processing technique

Cited by 10 publications

References 17 publications

Digital processing of signals from LaBr3:Ce scintillation detectors

Digital processing of signals from LaBr3:Ce scintillation detectors

Optimizing timing performance of CdTe detectors for PET

A General-Purpose Digital Pulse Shape Discrimination Algorithm

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Product

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Digital processing of signals from LaBr₃:Ce scintillation detectors

Digital processing of signals from LaBr₃:Ce scintillation detectors