Neutron imager with spaced diamond detector arrays

Patent metadata

Field	Value
Publication number	US-9958560-B1
Application number	US-201715795302-A
Country	US
Kind code	B1
Filing date	Oct 27, 2017
Priority date	Nov 1, 2016
Publication date	May 1, 2018
Grant date	May 1, 2018

Abstract

A neutron detector system, with a detector having a pair of spaced diamond detector layers, sandwiched between outer silicon layers. In response to incident neutrons, the detector system measures pulse heights and response times, and from those measurements, calculates the carbon recoil energy and time of flight of scattered neutrons. This data is further used to calculate a “direction cone”, which represents the approximate angle of arrival of the incident neutron. These direction cones can be used to image neutron events.

First claim

The invention claimed is:

1. A neutron detector system for detecting the approximate angle of arrival of an incident neutron; comprising:
a diamond detector, comprising two diamond detector layers, spaced a predetermined distance apart; two silicon layers, one of the two silicon layers associated with each diamond detector layer; wherein the diamond detector layers are both inner layers, and the two silicon layers are outer layers of a sandwich configuration of the diamond detector;
a pulse height analyzer, operable to measure the pulse height from the diamond detector layer that the incident neutron first encounters, thereby obtaining pulse height data;
a response time measurement circuit, operable to measure the response time of a recoil between the diamond detector layers, thereby obtaining response time data; and
a direction of arrival process programmed to calculate carbon recoil energy based on pulse height data, to calculate scattered neutron energy based on response time data, and to calculate a direction cone, representing an approximate direction of arrival of the incident neutron, based on carbon recoil energy and scattered neutron energy.

2. The system of claim 1 , further comprising an imager programmed to generate a neutron event image, based on several direction cones.

3. The system of claim 1 , wherein the direction of arrival process is further programmed to use coincidence logic to eliminate responses from particles not of interest.

4. The system of claim 1 , wherein each diamond detector is an array of diamond detector pieces.

5. The system of claim 1 , wherein each silicon layer is a thin silicon solid state detector layer.

6. The system of claim 1 , wherein the detector is operable to detect neutrons incident first on only one of the silicon layers.

7. The system of claim 1 , wherein the detector is operable to detect neutrons incident first on either silicon layer.

8. A method of detecting the arrival direction of an incident neutron, comprising:
scattering the incident neutron, using a diamond detector comprising: two diamond detector layers, spaced a predetermined distance apart; two silicon layers, one of the two silicon layers associated with each diamond detector layer; wherein the diamond detector layers are both inner layers, and the two silicon layers are outer layers of a sandwich configuration of the diamond detector;
measuring the energy of a carbon recoil resulting from the scattering;
measuring the time of flight of a scattered neutron within the detector;
calculating the energy of the scattered neutron, based on the time of flight; and
calculating a half angle, θ, of a cone around the direction of arrival of the incident neutron, based on carbon recoil energy and scattered neutron energy.

9. The method of claim 8 , wherein the energy of the carbon recoil is measured from pulse height information of the diamond detector first in the path of the incident neutron.

10. The method of claim 8 , wherein the energy of the scattered neutron is calculated further based on the separation distance of the detectors.

11. The method of claim 8 , further comprising eliminating measurements from energetic particles using coincidence logic.

12. The method of claim 8 , further comprising detecting large amplitude neutrons from only pulse height measurements.

13. The method of claim 8 , further comprising rejecting gamma rays based on time of flight measurements.

14. The method of claim 8 , wherein the detector is operable to detect neutrons incident first on only one of the silicon layers.

15. The system of claim 8 , wherein the detector is operable to detect neutrons incident first on either silicon layer.

Assignees

• Southwest Res Inst

Inventors

• Ogasawara Keiichi

Classifications

• G01T3/005

  Time-of-flight spectrometers · CPC title

• G01T3/003 Primary

  Recoil spectrometers (light-nuclei recoil ionisation tubes per se H01J47/1277) · CPC title

• G01T1/26 Primary

  with resistance detectors · CPC title

• G01T3/08

  with semiconductor detectors · CPC title