Neutron Detector With Interblended Liquid Scintillator

Patent metadata

Field	Value
Publication number	US-2016139280-A1
Application number	US-201414547092-A
Country	US
Kind code	A1
Filing date	Nov 18, 2014
Priority date	Nov 18, 2014
Publication date	May 19, 2016
Grant date	—

Abstract

A neutron detector that utilizes cells in which a liquid scintillator is contained in elongated detector tubes, with photo-detectors disposed at each end of the tube to measure scintillation light generated by incident neutrons. The liquid scintillator is an interblended mixture including an ionic liquid blended with a scintillation enhancer and/or a moderator and/or a controlled optical attenuator. A longitudinal position of an incident neutron is determined by the magnitudes of the scintillation light portions arriving at each photo-detector, which are proportional to the distances between the neutron interaction point and the photo-detectors. The cells are arranged in a closely-spaced parallel planar array to facilitate determining incident neutron location in two dimensions. A detector system utilizes a first detector array to detect fast neutrons, a thermalizer (e.g., polyethylene) to convert fast incident neutrons to thermal neutrons, and a second detector array to detect the thermal neutrons.

First claim

1 . A neutron detector cell comprising:
an elongated detector tube having a first end and an opposing second end and including a peripheral wall defining an enclosed channel, a liquid scintillator disposed in the elongated channel, said liquid scintillator including an ionic liquid blended with at least one of a scintillation enhancer, a moderator and a controlled optical attenuator; a first photo-detector optically coupled to the first end of said detector tube, said first photo-detector configured to detect a light pulse generated by said liquid scintillator, and to generate a first detection signal including a first light magnitude value indicating a first portion of said light pulse arriving at said first end of said detector tube; and a second photo-detector optically coupled to the second end of said detector tube, said second photo-detector configured to detect said light pulse and to generate a second detection signal including a second light magnitude value indicating a second portion of said light pulse arriving at said second end of said detector tube.

2 . The neutron detector cell of claim 1 , wherein the ionic liquid of the liquid scintillator comprises one or more anions derived from the group including derived from the group including [BF 4 ] − , [PF 6 ] − , [CF 3 SO 2 NSO 2 CF 3 ] − , [CF 3 SO 3 ] − , and [N(CN) 2 ] − , and one or more cations derived from the group including imidazolium, pyridinium, pyrimidinum, pyrazinium, pyrazolium, piperdinium and pyrrolidinium.

3 . The neutron detector cell of claim 2 , wherein the liquid scintillator comprises said ionic liquid blended with at least one of Athracene, an organic scintillator and inorganic scintillator.

4 . The neutron detector cell of claim 2 , wherein the liquid scintillator comprises said ionic liquid blended with at least one of Lithium and Boron.

5 . The neutron detector cell of claim 2 , wherein the liquid scintillator comprises said ionic liquid blended with at least one organic dye.

6 . The neutron detector cell of claim 5 , wherein the organic dye comprises an anthraquinone-based organic dye.

7 . The neutron detector of claim 1 , wherein the ionic liquid comprises a Room Temperature Ionic Liquid (RTIL).

8 . The neutron detector cell of claim 7 , wherein the liquid scintillator consists essentially of said RTIL blended with Anthracene.

9 . The neutron detector cell of claim 7 , wherein the liquid scintillator consists essentially of said RTIL blended with Lithium isotopes 6 Li and Boron isotopes 10 B.

10 . The neutron detector cell of claim 7 , wherein the liquid scintillator consists essentially of said RTIL blended with Lithium isotopes 6 Li, Boron isotopes 10 B and an organic dye.

11 . The neutron detector cell of claim 7 , wherein the liquid scintillator consists essentially of said RTIL blended with Lithium isotopes 6 Li, Boron isotopes 10 B, an organic dye and Antracene.

12 . The neutron detector cell of claim 1 , further comprising a tapered light guide disposed between the first end of said detector tube and said first photo-detector.

13 . The neutron detector cell of claim 1 ,
wherein the peripheral wall of the detector tube comprises one of plastic and glass, and wherein the neutron detector cell further comprises:
a reflective layer comprising a reflective material disposed on an outside surface of the peripheral wall; and
a light-sealing layer comprising a material that is opaque to black light disposed on an outside surface of the reflective layer.

14 . A neutron detector array including a plurality of detector cells, wherein each detector cell comprises:
an elongated detector tube having a first end and an opposing second end and including a peripheral wall defining an enclosed channel, a liquid scintillator disposed in the elongated channel, said liquid scintillator including an ionic liquid blended with at least one of a scintillation enhancer, a moderator and a controlled optical attenuator; a pair of photo-detectors respectively optically coupled to the first and second ends of said detector tube, each said photo-detector configured to detect light generated by said liquid scintillator disposed in said elongated detector tube, and to generate an associated detection signal including an associated light magnitude value indicating an amount of said detected light; and detection circuitry including a processor coupled to receive said detection signals generated by said pair of photo-detectors of each of said plurality of detector cells, said processor being configured to determine a transverse location of an incident neutron entering a receiver cell of said plurality of detector cells by identifying the receiver cell based on corresponding associated detection signals transmitted from said receiver cell, and said processor being further configured to determine a longitudinal location of said incident neutron by comparing said light magnitude values of said corresponding associated detection signals.

15 . A neutron detection system comprising:
a first detector array including a plurality of first detector cells, each first detector cell including an elongated first detector tube, a first liquid scintillator disposed in the elongated first detector tube, and a pair of first photo-detectors respectively optically coupled to opposing ends of said first elongated detector tube, each said first photo-detector configured to detect an associated first light portion generated by said first liquid scintillator, and to generate associated first detection signals including associated first light magnitude values; a second detector array including a plurality of second detector cells, each second detector cell including an elongated second detector tube, a second liquid scintillator disposed in the elongated second detector tube, and a pair of second photo-detectors respectively optically coupled to opposing ends of said second elongated detector tube, each said second photo-detector configured to detect an associated second light portion generated by said second liquid scintillator, and to generate associated second detection signals including associated second light magnitude values; and detection circuitry coupled to said first and second detector arrays and configured to determine the location of a neutron source by determining a first incident location corresponding to a first detection incident involving said neutron passing through said first detector array and a second incident location corresponding to a second detection incident corresponding to said neutron passing through said second detector array, wherein said first and second liquid scintillators including an ionic liquid blended with at least one of a scintillation enhancer, a moderator and a controlled optical attenuator.

16 . The neutron detection system of claim 15 ,
wherein said plurality of first detector cells are arranged in a first vertical plane, wherein said plurality of second detector cells are arranged in a second vertical plane, and wherein said first and second vertical planes are separated by gap distance in the range of 5 cm and 30 cm.

17 . The neutron detection system according to claim 16 , further comprising a thermalizer layer disposed between said first detector array and said second detector array.

18 . The neutron detection system according to claim 17 ,
wherein the first liquid scintillator comprises a first composition that is sensitive to fast neutrons, and wherein the second liquid scintillator comprises a second composition that is sensitiv

Assignees

• Palo Alto Res Ct Inc

Inventors

• Sahu Saroj Kumar
• Eldershaw Craig
• Sheridan Martin

Classifications

• G01T3/06 Primary

  with scintillation detectors · CPC title