Materials, method, and apparatus for detecting neutrons and ionizing radiation

Abstract

Embodiments of the invention provide a scintillator material, a scintillator system, and/or a method of detecting incident radiation using a scintillator material, or scintillator system, comprising a polymer material that comprises chromophores. Additional embodiments provide a scintillator material, scintillator system, and/or a method of detecting incident radiation using a sctintillator material, or scintillator system, comprising a polymer material having one, two, three, or more, organic dyes dissolved therein wherein the polymer material having the one, two, three, or more dyes dissolved therein comprises chromophores. At least one of the dyes, termed the base dye, has a concentration in the range 0.5 to 3.5 mol/L. In a specific embodiment, the base dye has a concentration in the range 1.0 to 3.0 mol/L. This base dye concentration is high enough to achieve a substantial triplet-triplet state annihilation rate despite the negligible diffusion of the dye in the rigid polymer matrix.

We claim: 
     
         1 . A scintillation system for detecting incident radiation, comprising:
 a scintillator composition for converting incident radiation to scintillation light wherein the scintillator composition comprises:   a matrix material with a plurality of base fluorescent dye molecules dissolved therein, wherein the matrix material is a solid organic material, wherein the matrix material with the plurality of base fluorescent dye molecules dissolved therein comprises a plurality of chromophores, wherein the plurality of chromophores have a chromophore average nearest neighbor distance in the range 0.5 to 12 Angstroms;   wherein the plurality of chromophores produces the scintillation light upon excitation;   wherein the scintillation light has a prompt time component and a delayed time component, wherein the prompt time component and the delayed time component provide information so as to allow distinguishing between scintillation light created by neutrons and scintillation light created by gamma rays.   
     
     
         2 . The scintillation system according to  claim 1 , wherein the plurality of base fluorescent dye molecules comprises a plurality of base fluorescent dye chromophores, wherein each base fluorescent dye molecule comprise one or more base fluorescent dye chromophores of the plurality of base fluorescent dye chromophores, wherein the plurality of chromophores comprises the plurality of base fluorescent dye chromophores, wherein the plurality of base fluorescent dye chromophores have a base fluorescent dye chromophore average nearest neighbor distance in the range 0.5 to 12 Angstroms. 
     
     
         3 . The scintillation system according to  claim 1 , wherein the plurality of chromophores comprises a plurality of matrix material chromophores, wherein the matrix material chromophores have a matrix material chromophore average nearest neighbor distance in the range 0.5 to 12 Angstroms. 
     
     
         4 . The scintillation system of  claim 1 , wherein the prompt time component has a prompt intensity (I P ) and a prompt time constant ( T   P ), and the delayed time component has a delayed intensity (I D ) and a delayed time constant ( T   D ). 
     
     
         5 . The scintillation system according to  claim 4 , wherein I P   , T   P , I D , and  T   D  are such that a difference between a mean of a gamma ray scintillation signal due to gamma rays incident on the scintillation system and a mean of a neutron scintillation signal due to neutrons incident on the scintillation system divided by a sum of a FWHM of the gamma ray scintillation signal and a FWHM of the neutron scintillation signal is at least 2. 
     
     
         6 . The scintillation system according to  claim 5 , wherein the difference divide by the sum is at least 3. 
     
     
         7 . The scintillation system of  claim 1 , further comprising a receiver, wherein the receiver records and analyzes the scintillation light from the scintillator composition and determines whether neutrons were incident on the scintillation system. 
     
     
         8 . The scintillation system of  claim 1 , wherein the matrix material is a polymeric material. 
     
     
         9 . The scintillation system according to  claim 8 , wherein the matrix material is transparent to the scintillation light. 
     
     
         10 . The scintillation system of  claim 2 , wherein the matrix material comprises one or more materials selected from the group consisting of: polystyrene, polyvinyltoluene, polyvinylxylene, polyvinylnaphthalene, polyvinylbiphenyl, polyvinylcarbazole, polycarbonate, polyvinylcarbonate, N-vinyk Pyrrolidone, and polymethylmethacrylate. 
     
     
         11 . The scintillation system of  claim 1 , wherein the matrix material is a cross-linked polymeric material. 
     
     
         12 . The scintillation system of  claim 2 , wherein the plurality of base fluorescent dye molecules has a concentration in the range 0.3 to 3.5 mol/L. 
     
     
         13 . The scintillation system of  claim 2 , wherein the plurality of base fluorescent dye molecules has a concentration in the range 0.5 to 1.5 mol/L. 
     
     
         14 . The scintillation system of  claim 2 , wherein a first excited singlet state of one of the plurality of base fluorescent dye chromophores has a quantum yield >0.25. 
     
     
         15 . The scintillation system of  claim 2 , wherein a first excited singlet state of one of the plurality of base fluorescent dye chromophores has a quantum yield >0.5 
     
     
         16 . The scintillation system of  claim 2 , wherein a first excited singlet state of one of the plurality of base fluorescent dye chromophores has a quantum yield >0.75. 
     
     
         17 . The scintillation system of  claim 2 , wherein a first excited triplet state of one of the plurality of base fluorescent dye chromophores has an annihilation rate with the first excited triplet state of its nearest neighbor that is determined by a concentration of the plurality of base fluorescent dye molecules. 
     
     
         18 . The scintillation system of  claim 2 , wherein the plurality of base fluorescent dye molecules comprises a polycyclic aromatic dye. 
     
     
         19 . A method for detecting incident radiation, comprising:
 positioning a scintillation system in a region of interest, wherein the scintillation system comprises:
 a scintillator composition for converting the incident radiation to scintillation light wherein the scintillator composition comprises: 
 a matrix material, wherein the matrix material is a solid organic material, wherein the matrix material comprises chromophores, wherein the chromophores have an average nearest neighbor distance in the range of 0.5 to 12 Angstroms; 
 wherein the chromophores produce the scintillation light upon excitation; 
 wherein the prompt time component and the delayed time component provide information so as to allow distinguishing between scintillation light created by neutrons and scintillation light created by gamma rays; 
 receiving the scintillation light; and 
 determining form the received scintillation light whether neutrons were incident on the scintillation system. 
   
     
     
         20 . A scintillator composition for converting the incident radiation to scintillation light, comprising:
 a matrix material with a plurality of base fluorescent dye molecules dissolved therein, wherein the matrix material is a solid organic material, wherein the matrix material with the plurality of base fluorescent dye molecules dissolved therein comprises a plurality of chromophores, wherein the plurality of chromophores have a chromophore average nearest neighbor distance in the range 0.5 to 12 Angstroms;   wherein the plurality of chromophores produces the scintillation light upon excitation;   wherein the scintillation light has a prompt time component and a delayed time component, wherein the prompt time component and the delayed time component provide information so as to allow distinguishing between scintillation light created by neutrons and scintillation light created by gamma rays.