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Title: Modeling Time Dispersion Due to Optical Path Length Differences in Scintillation Detectors

In this paper, we characterize the nature of the time dispersion in scintillation detectors caused by path length differences of the scintillation photons as they travel from their generation point to the photodetector. Using Monte Carlo simulation, we find that the initial portion of the distribution (which is the only portion that affects the timing resolution) can usually be modeled by an exponential decay. The peak amplitude and decay time depend both on the geometry of the crystal, the position within the crystal that the scintillation light originates from, and the surface finish. In a rectangular parallelpiped LSO crystal with 3 mm × 3 mm cross section and polished surfaces, the decay time ranges from 10 ps (for interactions 1 mm from the photodetector) up to 80 ps (for interactions 50 mm from the photodetector). Over that same range of distances, the peak amplitude ranges from 100% (defined as the peak amplitude for interactions 1 mm from the photodetector) down to 4% for interactions 50 mm from the photodetector. Higher values for the decay time are obtained for rough surfaces, but the exact value depends on the simulation details. Finally, estimates for the decay time and peak amplitude can bemore » made for different cross section sizes via simple scaling arguments.« less
Authors:
 [1] ;  [1] ;  [1]
  1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Publication Date:
Grant/Contract Number:
AC02-05CH11231; R01-EB006085; R01-EB012524; R21-EB012599
Type:
Accepted Manuscript
Journal Name:
Acta Physica Polonica. Series B, Proceedings Supplement
Additional Journal Information:
Journal Volume: 7; Journal Issue: 4; Journal ID: ISSN 1899-2358
Publisher:
Jagiellonian University
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); National Inst. of Health (NIH) (United States)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS
OSTI Identifier:
1407212

Moses, W. W., Choong, W. -S., and Derenzo, S. E.. Modeling Time Dispersion Due to Optical Path Length Differences in Scintillation Detectors. United States: N. p., Web. doi:10.5506/APhysPolBSupp.7.725.
Moses, W. W., Choong, W. -S., & Derenzo, S. E.. Modeling Time Dispersion Due to Optical Path Length Differences in Scintillation Detectors. United States. doi:10.5506/APhysPolBSupp.7.725.
Moses, W. W., Choong, W. -S., and Derenzo, S. E.. 2014. "Modeling Time Dispersion Due to Optical Path Length Differences in Scintillation Detectors". United States. doi:10.5506/APhysPolBSupp.7.725. https://www.osti.gov/servlets/purl/1407212.
@article{osti_1407212,
title = {Modeling Time Dispersion Due to Optical Path Length Differences in Scintillation Detectors},
author = {Moses, W. W. and Choong, W. -S. and Derenzo, S. E.},
abstractNote = {In this paper, we characterize the nature of the time dispersion in scintillation detectors caused by path length differences of the scintillation photons as they travel from their generation point to the photodetector. Using Monte Carlo simulation, we find that the initial portion of the distribution (which is the only portion that affects the timing resolution) can usually be modeled by an exponential decay. The peak amplitude and decay time depend both on the geometry of the crystal, the position within the crystal that the scintillation light originates from, and the surface finish. In a rectangular parallelpiped LSO crystal with 3 mm × 3 mm cross section and polished surfaces, the decay time ranges from 10 ps (for interactions 1 mm from the photodetector) up to 80 ps (for interactions 50 mm from the photodetector). Over that same range of distances, the peak amplitude ranges from 100% (defined as the peak amplitude for interactions 1 mm from the photodetector) down to 4% for interactions 50 mm from the photodetector. Higher values for the decay time are obtained for rough surfaces, but the exact value depends on the simulation details. Finally, estimates for the decay time and peak amplitude can be made for different cross section sizes via simple scaling arguments.},
doi = {10.5506/APhysPolBSupp.7.725},
journal = {Acta Physica Polonica. Series B, Proceedings Supplement},
number = 4,
volume = 7,
place = {United States},
year = {2014},
month = {8}
}