Neutron spectrometer

Abstract

A neutron spectrometer that is more accurate, faster, and more-portable than conventional spectrometers includes an organic scintillator responsive to neutrons and gammas and an inorganic scintillator that captures neutrons. A processor receives signals representative of scintillations in the organic scintillator and in the inorganic scintillator and discriminates neutron signals from gamma signals. The processor also determines pulse areas for neutron moderating signals and performs unfolding based on the determined pulse areas to produce a neutron energy spectrum and/or dose information.

What is claimed is: 
     
         1 . A neutron detector comprising:
 an organic moderator;   an inorganic scintillator, comprising lithium gadolinium borate, that captures neutrons;   a processor which
 (1) receives signals representative of scintillations in the inorganic scintillator and identifies signals resulting from capture in gadolinium and discriminates the signals resulting from capture in gadolinium from other signals; and 
 (2) using the signals that were identified as resulting from capture in gadolinium and that were discriminated from other signals to generate and output data of neutrons incident on the neutron detector. 
   
     
     
         2 . A neutron detector as set forth in  claim 1 , wherein the inorganic scintillator comprises cerium or any other activator. 
     
     
         3 . A neutron detector as set forth in  claim 1 , wherein the processor identifies signals resulting from capture in gadolinium and discriminates the signals from other signals based at least on pulse shape. 
     
     
         4 . A neutron detector as set forth in  claim 1 , wherein the processor identifies signals resulting from capture in gadolinium and discriminates the signals from other signals based at least on pulse area. 
     
     
         5 . A neutron detector as set forth in  claim 1 , wherein the processor identifies signals resulting from capture in gadolinium and discriminates the signals from other signals based at least on pulse length. 
     
     
         6 . A neutron detector as set forth in  claim 1 , wherein the processor identifies signals resulting from capture in gadolinium and discriminates the signals from other signals based at least on scintillation in the inorganic scintillator. 
     
     
         7 . A neutron detector as set forth in  claim 1 , wherein the processor identifies signals resulting from capture in gadolinium and discriminates the signals from other signals based at least on scintillation in the organic moderator. 
     
     
         8 . A neutron detector as set forth in  claim 1 , wherein the organic moderator comprises poly-vinyl-toluene or other hydrogenous organic moderator. 
     
     
         9 . A neutron detector as set forth in  claim 1 , wherein the processor performs integration to determine areas. 
     
     
         10 . A neutron detector as set forth in  claim 1 , wherein the processor curve fits decreasing edge data points to calculate a pulse decay constant. 
     
     
         11 . A neutron detector as set forth in  claim 1 , wherein the inorganic scintillator comprises Li 6 GdB 3 O 9 :Ce wherein the inorganic scintillator contains Gd-157. 
     
     
         12 . A neutron detector as set forth in  claim 1 , wherein the inorganic scintillator comprises  6 Li 6 Gd 10 B 3 O 9 :Ce wherein  6 Li,  10 B, and  157 Gd neutron captures are identified by the processor by shape characteristic of Ce emission, and  157 Gd captures are processed by the processor through neutron analysis software. 
     
     
         13 . A neutron detector as set forth in  claim 1 , wherein some gammas interact with Gd and produce a scintillation, others deposit collision energy at a Gd site in LGB crystal and produce a Ce scintillation, which produces pulses that are identified and separated by the processor. 
     
     
         14 . A neutron detector as set forth in  claim 1 , wherein the processor receives signals representative of scintillations in the organic moderator and in the inorganic scintillator, the signals including signals representative of interactions of neutrons with  157 Gd. 
     
     
         15 . A neutron detector as set forth in  claim 1 , wherein the organic moderator is a scintillator.