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Title: Electron cascades in sensors for optical detection of ionizing radiation

A new class of high-speed detectors, called RadOptic detectors, measures ionizing radiation incident on a transparent semiconductor by sensing changes in the refractive index with an optical probe beam. We describe the role of radiation-initiated electron cascades in setting the sensitivity and the spatial and temporal resolution of RadOptic detectors. We model electron cascades with both analytical and Monte Carlo computational methods. We find that the timescale for the development of an electron cascade is less than of order 100 fs and is not expected to affect the time response of a detector. The characteristic size of the electron cloud is typically less than 2 μm, enabling high spatial resolution in imaging systems. The electron-hole pair density created by single x-rays is much smaller than the saturation density and, therefore, single events should not saturate the detector.
Authors:
; ; ;  [1]
  1. Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
Publication Date:
OSTI Identifier:
22217919
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 114; Journal Issue: 15; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; ELECTRON DETECTION; IONIZATION; MONTE CARLO METHOD; REFRACTIVE INDEX; SEMICONDUCTOR MATERIALS; SENSITIVITY; SENSORS; SPATIAL RESOLUTION; X RADIATION