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Title: Cadmium zinc telluride based infrared interferometry for X-ray detection

Cadmium Zinc Telluride (CZT) is a wide band gap semiconductor for room temperature radiation detection. The electro-optic Pockels effect of the material has been exploited in the past to study electric field non-uniformities and their consequence on conventional detector signals in CZT, by imaging the intensity distribution of infrared (IR) light transmitted through a device placed between crossed polarizers. Recently, quantitative monitoring of extremely high intensity neutron pulses through the change of transmitted IR intensity was demonstrated, offering the advantage to place sensitive electronics outside the measured radiation field. In this work, we demonstrate that X-ray intensity can be deduced directly from measuring the change in phase of 1550 nm laser light transmitted through a 7 × 7 × 2 mm{sup 3} CZT based Pockels cell in a simple Mach Zehnder interferometer. X-rays produced by a 50 kVp Mo X-ray tube incident on the CZT cathode surface placed at 7 mm distance cause a linearly increasing phase shift above 0.3 mA tube current, with 1.58 ± 0.02 rad per mA for an applied bias of 500 V across the 2 mm thick device. Pockels images confirm that the sample properties are in agreement with the literature, exhibiting electric field enhancement near the cathode under irradiation, which may cause themore » non-linearity at low X-ray tube anode current settings. The laser used to probe the X-ray intensity causes itself some space charge, whose spatial distribution does not seem to be exclusively determined by the incident laser position, i.e., charge carrier generation location, with respect to the electrodes.« less
Authors:
;  [1] ;  [1] ;  [2] ; ; ;  [3]
  1. Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom)
  2. (United Kingdom)
  3. AWE Aldermaston, Reading RG7 4PR (United Kingdom)
Publication Date:
OSTI Identifier:
22412631
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 6; Other Information: (c) 2015 Crown; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CADMIUM COMPOUNDS; CATHODES; CHARGE CARRIERS; ELECTRIC FIELDS; INTERFEROMETRY; IRRADIATION; MACH-ZEHNDER INTERFEROMETER; PHASE SHIFT; POCKELS CELL; SEMICONDUCTOR MATERIALS; SPACE CHARGE; SPATIAL DISTRIBUTION; SURFACES; TEMPERATURE RANGE 0273-0400 K; VISIBLE RADIATION; X-RAY DETECTION; X-RAY TUBES; ZINC TELLURIDES