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Title: Portal radiation monitor

Abstract

A portal radiation monitor combines 0.1% FAR with high sensitivity to special nuclear material. The monitor utilizes pulse shape discrimination, dynamic compression of the photomultiplier output and scintillators sized to maintain efficiency over the entire portal area.

Inventors:
 [1]
  1. (Albuquerque, NM)
Publication Date:
Research Org.:
AT & T CORP
OSTI Identifier:
865397
Patent Number(s):
US 4509042
Assignee:
United States of America as represented by United States (Washington, DC) SNL
DOE Contract Number:
AC04-76DP00789
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
portal; radiation; monitor; combines; sensitivity; special; nuclear; material; utilizes; pulse; shape; discrimination; dynamic; compression; photomultiplier; output; scintillators; sized; maintain; efficiency; entire; pulse shape; nuclear material; radiation monitor; special nuclear; monitor utilizes; multiplier output; portal radiation; /340/250/

Citation Formats

Kruse, Lyle W. Portal radiation monitor. United States: N. p., 1985. Web.
Kruse, Lyle W. Portal radiation monitor. United States.
Kruse, Lyle W. Tue . "Portal radiation monitor". United States. doi:. https://www.osti.gov/servlets/purl/865397.
@article{osti_865397,
title = {Portal radiation monitor},
author = {Kruse, Lyle W.},
abstractNote = {A portal radiation monitor combines 0.1% FAR with high sensitivity to special nuclear material. The monitor utilizes pulse shape discrimination, dynamic compression of the photomultiplier output and scintillators sized to maintain efficiency over the entire portal area.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Jan 01 00:00:00 EST 1985},
month = {Tue Jan 01 00:00:00 EST 1985}
}

Patent:

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  • A portal monitoring system has a cosmic ray charged particle tracker with a plurality of drift cells. The drift cells, which can be for example aluminum drift tubes, can be arranged at least above and below a volume to be scanned to thereby track incoming and outgoing charged particles, such as cosmic ray muons, whilst also detecting gamma rays. The system can selectively detect devices or materials, such as iron, lead, gold and/or tungsten, occupying the volume from multiple scattering of the charged particles passing through the volume and can also detect any radioactive sources occupying the volume from gammamore » rays emitted therefrom. If necessary, the drift tubes can be sealed to eliminate the need for a gas handling system. The system can be employed to inspect occupied vehicles at border crossings for nuclear threat objects.« less
  • A portal radiation monitor combines 0.1% FAR with high sensitivity to special nuclear material. The monitor utilizes pulse shape discrimination, dynamic compression of the photomultiplier output and scintillators sized to maintain efficiency over the entire portal area.
  • A portal radiation monitor combines .1% FAR with high sensitivity to special nuclear material. The monitor utilizes pulse shape discrimination, dynamic compression of the photomultiplier output and scintillators sized to maintain efficiency over the entire portal area.
  • A large area neutron proportional counter is constructed utilizing a large sealed metal box. The interior walls of the box are coated with /sup 6/Li enriched metal. A multicelled proportional counter structure within the internal space defined by the box is fabricated using a hydrogenous plastic. The interior of the box is filled with a counting gas. Wires running through the box, and insulated therefrom, are raised to a suitably high potential so that the counting gas functions in the proportional region to amplify and collect charge from ionizing events in the gas, the wires acting as a anodes andmore » the box as cathode. The cell dimensions are chosen so that /sup 6/Li(n,a)/sup 3/H reaction products will, with high probability, stop in the gas. Compton electrons, on the other hand, will mostly be stopped in the walls or in the hydrogenous plastic cell boundaries. An array of such counters may be utilized for detection of neutron emitting materials passing through a portal.« less
  • A water Cerenkov-based neutron and high energy gamma ray detector and radiation portal monitoring system using water doped with a Gadolinium (Gd)-based compound as the Cerenkov radiator. An optically opaque enclosure is provided surrounding a detection chamber filled with the Cerenkov radiator, and photomultipliers are optically connected to the detect Cerenkov radiation generated by the Cerenkov radiator from incident high energy gamma rays or gamma rays induced by neutron capture on the Gd of incident neutrons from a fission source. The PMT signals are then used to determine time correlations indicative of neutron multiplicity events characteristic of a fission source.