US 2018/0003832 A1Published application

Accelerating fissile material detection with a neutron source

AssigneeLawrence Livermore National Security, LLC

InventorsMark S. Rowland, Neal J. Snyderman

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Abstract

A neutron detector system for discriminating fissile material from non-fissile material wherein a digital data acquisition unit collects data at high rate, and in real-time processes large volumes of data directly to count neutrons from the unknown source and detecting excess grouped neutrons to identify fission in the unknown source. The system includes a Poisson neutron generator for in-beam interrogation of a possible fissile neutron source and a DC power supply that exhibits electrical ripple on the order of less than one part per million. Certain voltage multiplier circuits, such as Cockroft-Walton voltage multipliers, are used to enhance the effective of series resistor-inductor circuits components to reduce the ripple associated with traditional AC rectified, high voltage DC power supplies.

Claims7

Dependent claims

A system for characterizing a radiation source as fissile material or non-fissile material, comprising:

a neutron generator configured to irradiate the radiation source by inducing radiation in the radiation source;
a detector configured to receive and count neutrons emitted from the radiation source;
and
an analyzer component coupled to the detector and configured to determine the number of times that a group of n simultaneously emitted neutrons is observed from the radiation source after a defined measurement time period is repeated a defined number of times to derive a neutron count measurement, subtract an expected number of pairs of neutrons emitted by a hypothetical non-fission Poisson neutron source embodied in the neutron generator during the measurement time period from the number of pairs of observed neutrons derived from the neutron count measurement;
characterize the radiation source as fissile material if the number of pairs of observed neutrons exceeds the expected number of pairs of neutrons in at least a portion of a histogram derived for the Poisson neutron source as compared to a histogram derived for the neutron count measurement.

2 more elements

A system characterizing a radiation source as fissile material or non-fissile material, comprising the steps of:

a neutron generator irradiating the radiation source by inducing radiation in the radiation source;
a detector receiving and counting neutrons emitted from the radiation source in a detector circuit placed proximate the neutron source;
an analyzer determining the number of times that a group of n simultaneously emitted neutrons is observed from the radiation source after a defined measurement time period is repeated a defined number of times to derive a neutron count measurement, and subtracting an expected number of pairs of neutrons emitted by a hypothetical non-fission Poisson neutron source embodied in the neutron generator during the measurement time period from the number of pairs of observed neutrons derived from the neutron count measurement;
and
an analyzer component characterizing the radiation source as fissile material if the number of pairs of observed neutrons exceeds the expected number of pairs of neutrons in at least a portion of a histogram derived for the Poisson neutron source as compared to a histogram derived for the neutron count measurement.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/419,916Filed 30 Jan 2017
Priority: 24 Sep 2004
Published: 4 Jan 2018
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

G01T 3/00
Measuring neutron radiation
G01N 23/005
Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 –…: by…
G01V 5/281
Detecting prohibited goods, e.g. weapons, explosives, hazardous substances, contraband or smuggled objects: detecting special nuclear material…
G01T
Measurement of nuclear or x-radiation

Family

Application60/612,968Us provisional application · filed 24 Sep 2004
Application11/233,228Continuation in part · filed 21 Sep 2005
Application12/712,040Continuation in part · filed 24 Feb 2010
Application14/213,502Division · filed 14 Mar 2014
Application15/419,916Division
Application14/213,502Continuation in part
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