Neutron detector using neutron absorbing scintillating particulates in plastic

Abstract

A neutron detector composed of a matrix of scintillating particles imbedded in a lithiated glass is disclosed. The neutron detector detects the neutrons by absorbing the neutron in the 6Li isotope which has been enriched from the natural isotopic ratio to a commercial ninety five percent. The utility of the detector is optimized by suitably selecting scintillating particle sizes in the range of the alpha and the triton. Nominal particle sizes are in the range of five to twenty five microns depending upon the specific scintillating particle selected.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application No. 60 / 476,001, filed Jun. 5, 2003.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] Not Applicable BACKGROUND OF THE INVENTION [0003] 1. Field of Invention [0004] The field of invention is neutron detectors. More particularly, the present invention relates to a neutron detector having solid absorbers. [0005] 2. Description of the Related Art [0006] Neutron detectors are useful in many applications. One such application is the monitoring of fissile material in storage containers, in spent nuclear fuel and in waste. Limiting the unauthorized transfer of fissile material is endorsed by all countries participating in the International Atomic Energy Agency (IAEA) program. The purpose of the IAEA program is to limit access to those materials needed for constructing a nuclear weapon of mass destruction. [0007] A major effort is being made to provide robus...

AI Technical Summary

Benefits of technology

[0066] The present invention describes the means for manufacturing a neutron detector so that a large volume can be observed for the detection of absorbed neutrons. Neutron absorbing lithiated / scintillating particulates are uniformly distributed within a clear, optically-transparent plastic matrix. Scintillation emission is detected by either direct coupling of the optically-transparent plastic to a photomultiplier or via a wavelength shifting fiber coupled between the optically-transparent plastic block and a photomultiplier. Multiple blocks may each have a dedicated wavelength shifting fiber. In one embodiment, a plurality of fibers is coupled to the face of one multi-anode photomultiplier allowing for a lower cost monitoring system. The volume that can be made sensitive to this neutron detector design is very large. The present invention provides a means for interrogating large volumes of scintillation material for neutron absorption using a basic design as a building block that is replicated as required.

[0067] The invention has application to the quantitation of the fissile mass within a container using the neutron absorbing plastic in place of 3He tubes. A technology is commercialized that was developed over several years at the Los Alamos National Laboratory. The present invention offers an alternate means of detecting neutrons having the advantage that the cost of the neutron absorbing element is lower cost than the gas tubes and can be produced in large quantity by an extrusion process.

Problems solved by technology

The volume that can be made sensitive to this neutron detector design is very large.

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