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Title: Threshold self-powered gamma detector for use as a monitor of power in a nuclear reactor

Abstract

A self-powered gamma monitor for placement near the core of a nuclear reactor comprises a lead prism surrounded by a coaxial thin nickel sheet, the combination forming a collector. A coaxial polyethylene electron barrier encloses the collector and is separated from the nickel sheet by a vacuum region. The electron barrier is enclosed by a coaxial stainless steel emitter which, in turn, is enclosed within a lead casing. When the detector is placed in a flux of gamma rays, a measure of the current flow in an external circuit between emitter and collector provides a measure of the power level of the reactor.

Inventors:
 [1];  [2]
  1. (Chicago, IL)
  2. (Darien, IL)
Publication Date:
Research Org.:
Argonne National Laboratory (ANL), Argonne, IL
OSTI Identifier:
863094
Patent Number(s):
US 4091288
Assignee:
United States of America as represented by United States (Washington, DC) ANL
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
threshold; self-powered; gamma; detector; monitor; power; nuclear; reactor; placement; near; core; comprises; lead; prism; surrounded; coaxial; nickel; sheet; combination; forming; collector; polyethylene; electron; barrier; encloses; separated; vacuum; region; enclosed; stainless; steel; emitter; casing; placed; flux; rays; measure; current; flow; external; circuit; provides; level; external circuit; gamma rays; gamma ray; power level; nuclear reactor; stainless steel; current flow; reactor comprises; self-powered gamma; vacuum region; gamma detector; /250/

Citation Formats

LeVert, Francis E., and Cox, Samson A.. Threshold self-powered gamma detector for use as a monitor of power in a nuclear reactor. United States: N. p., 1978. Web.
LeVert, Francis E., & Cox, Samson A.. Threshold self-powered gamma detector for use as a monitor of power in a nuclear reactor. United States.
LeVert, Francis E., and Cox, Samson A.. Sun . "Threshold self-powered gamma detector for use as a monitor of power in a nuclear reactor". United States. doi:. https://www.osti.gov/servlets/purl/863094.
@article{osti_863094,
title = {Threshold self-powered gamma detector for use as a monitor of power in a nuclear reactor},
author = {LeVert, Francis E. and Cox, Samson A.},
abstractNote = {A self-powered gamma monitor for placement near the core of a nuclear reactor comprises a lead prism surrounded by a coaxial thin nickel sheet, the combination forming a collector. A coaxial polyethylene electron barrier encloses the collector and is separated from the nickel sheet by a vacuum region. The electron barrier is enclosed by a coaxial stainless steel emitter which, in turn, is enclosed within a lead casing. When the detector is placed in a flux of gamma rays, a measure of the current flow in an external circuit between emitter and collector provides a measure of the power level of the reactor.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 1978},
month = {Sun Jan 01 00:00:00 EST 1978}
}

Patent:

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  • A self-powered gamma monitor for placement near the core of a nuclear reactor comprises a lead prism surrounded by a coaxial thin nickel sheet, the combination forming a collector. A coaxial polyethylene electron barrier encloses the collector and is separated from the nickel sheet by a vacuum region. The electron barrier is enclosed by a coaxial stainless steel emitter which, in turn, is enclosed within a lead casing. When the detector is placed in a flux of gamma rays, a measure of the current flow in an external circuit between emitter and collector provides a measure of the power levelmore » of the reactor.« less
  • A study of a threshold self-powered gamma detector for use as a nuclear reactor power monitor was conducted. Measurements were performed to ascertain whether certain detector material arrangements could be used to obtain significant discrimination against low energy gammas. Results indicating agreement between detector response and reactor power output are presented. Evidence of rejection of low energy gammas by the detector is presented. The simplicity of construction and ruggedness of the detector are also discussed.
  • A study of a fully encapsulated directional self-powered gamma ray detector designed for localized in core measurements in a nuclear reactor was conducted. The detector consisted of a multilayer arrangement of a metal-dielectric-metal-dielectric-metal structure. The dielectric material was made of two plates of unequal thicknesses which were placed on opposite sides of the central metal plate. The direction discrimination exhibited by the detector was attributed to the combined effect of electron ranges, Photo-Compton electron generation rates, and the presence of E-fields in the unequal thicknesses of dielectric material. Results showing the response of the detector when it was placed inmore » a gamma ray field with a known anisotropic component are presented.« less
  • The purpose of this research was to develop a large area self-powered gamma detector (LASPGD) capable of detecting the movement of sealed radiation sources into and out of industrial radiographic units and to construct a prototype source position monitor (SPM) for these units utilizing the LASPGD. Prototype isotropic and directional LASPGDs, with solid and inert gas dielectrics, were developed and extensively tested using calibrated gamma sources (i.e., Cs-137, and Co-60). The sensitivities of the isotropic detectors, with inert gas dielectrics, were found to be approximately a factor of ten greater than those measured for the solid dielectric LASPGDs. Directionally sensitivemore » self-powered detectors were found to exhibit a forward-to-back hemispherical sensitivity ratio of approximately 2 to 1. Industrial radiographic units containing Ir-192 sources with different activities were used to test the performance of the SPM. The SPM, which utilized a gas dielectric LASPGD, performed as designed. That is, the current generated in the LASPGD was converted to a voltage, amplified and used to control the on/off state of an incandescent lamp. The incandescent lamp, which functions as the source/out warning indicator, flashes at a rate of one flash per second when the source is in use (i.e. out of its shield).« less
  • An improved response gamma sensitive self-powered detector is provided by forming the conductive central emitter as a tubular member. Low density, non-attenuating insulating means is disposed within the tubular emitter and about the tubular emitter spacing it from the coaxial outer conductive collector.