title: Exploring the limiting timing resolution for large volume CZT detectors with waveform analysis.
abstract: This paper presents a study for exploring the limiting timing resolution that can be achieved with a large volume 3-D position sensitive CZT detector. The interaction timing information was obtained by fitting the measured cathode waveforms to pre-defined waveform models. We compared the results from using several different waveform models. Timing resolutions, of ~9.5 ns for 511 keV full-energy events and ~11.6 ns for all detected events with energy deposition above 250 keV, were achieved with a detailed modeling of the cathode waveform as a function of interaction location and energy deposition. This detailed modeling also allowed us to derive a theoretical lower bound for the error on estimated interaction timing. Both experimental results and theoretical predications matched well, which indicated that the best timing resolution achievable in the 1 cm3CZT detector tested is ~10 ns. It is also showed that the correlation between sampled amplitudes in cathode waveforms is an important limiting factor for the achievable timing resolution.
authors.affiliation: Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 1906 Cooley Building, 2355 Bonisteel Blvd., Ann Arbor MI 48109, USA.
authors.forename: L J
authors.initials: LJ
authors.lastname: Meng
authors.affiliation: Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 1906 Cooley Building, 2355 Bonisteel Blvd., Ann Arbor MI 48109, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: He
keywords: Large volume 3-D position sensitive czt; Timing resolution; Waveform analysis