Isotope specific arbitrary material sorter
View Patent ↗A laser-based mono-energetic gamma-ray source is used to provide a rapid and unique, isotope specific method for sorting materials. The objects to be sorted are passed on a conveyor in front of a MEGa-ray beam which has been tuned to the nuclear resonance fluorescence transition of the desired material. As the material containing the desired isotope traverses the beam, a reduction in the transmitted MEGa-ray beam occurs. Alternately, the laser-based mono-energetic gamma-ray source is used to provide non-destructive and non-intrusive, quantitative determination of the absolute amount of a specific isotope contained within pipe as part of a moving fluid or quasi-fluid material stream.
1. A method, comprising:
providing a beam of mono-energetic gamma rays of a predetermined energy level selected to induce nuclear resonance fluorescence in a predetermined target isotope;
conveying material through said beam to produce a transmitted beam, wherein if said material comprises said target isotope, the power of said transmitted beam will be attenuated;
detecting said reduction in power to identify target material comprising said isotope of interest and to further identity non-target material that does not comprise said isotope of interest; and
mechanically separating said target material from said non-target material, wherein the step of providing a beam of mono-energetic gamma rays comprises:
generating, with an electron source, a train of spaced electron bunches;
accelerating, in an RF linear accelerator, said electron bunches into a laser-electron beam interaction region to produce accelerated electron bunches, wherein the transit time of each of said accelerated electron bunches through said laser-electron beam interaction region is both greater than the duration of said accelerated electron bunch and greater than the spacing between said spaced electron bunches; and
producing, with a laser system, a laser pulse having a duration at least as long as a transit time of said laser pulse through said laser-electron beam interaction region, wherein said laser system is arranged so that said laser pulse traverses said laser-electron beam interaction region to interact with all of said accelerated electron bunches and thereby produce said beam of monoenergetic gamma-rays.
2. The method of claim 1 , wherein said duration of said laser pulse is substantially equal to at least a total length of said train of spaced electron bunches so that a single pass of said laser pulse through the laser-electron beam interaction region interacts with all of the accelerated electron bunches of said train.
3. The method of claim 1 , wherein said duration of said laser pulse is substantially equal to a sub-multiple of a total length of said train of spaced electron bunches and said laser system is arranged to recirculate said laser pulse through said laser-electron beam interaction region for a predetermined number of passes equal to an inverse of said sub-multiple.
4. The method of claim 1 , wherein the spacing frequency of said electron bunches is the same as or correlated to the RF frequency of said RF linear accelerator so that an electron bunch is present for every cycle of the RF frequency.
5. The method of claim 1 , wherein said gamma-rays comprise a fractional bandwidth of 10E-3 or less.
6. A method, comprising:
providing a beam of mono-energetic gamma rays of a predetermined energy level selected to induce nuclear resonance fluorescence in a predetermined target isotope;
conveying material through said beam to produce a transmitted beam, wherein if said material comprises said target isotope, the power of said transmitted beam will be attenuated;
detecting said reduction in power to identify target material comprising said isotope of interest and to further identity non-target material that does not comprise said isotope of interest; and
mechanically separating said target material from said non-target material, wherein the step of detecting is carried out with a detector comprising:
a first structure;
a first integrating detector operatively positioned to detect a signal A from said first structure;
a second structure; and
a second integrating detector operatively positioned to detect a signal B from said second structure, wherein said first structure and said second structure comprise the same atomic material, wherein said first structure comprises a portion A that consist essentially of a first isotope, wherein said second structure comprises a portion B that consists essentially of a second isotope, wherein said first structure and said second structure are configured to intercept at least some portion of said beam of monoenergetic gamma-rays.
7. The method of claim 6 , wherein said first structure comprises a first foil and wherein said second structure comprises a second foil.
8. The method of claim 6 , wherein said first isotope consists of U 235 and wherein said second isotope consists of U 238 .
9. The method of claim 6 , wherein said first isotope consists of PU 241 and wherein said second isotope consists of PU 239 .
10. An apparatus, comprising;
a mono-energetic gamma ray source adapted to produce a beam of mono-energetic gamma rays of a predetermined energy level selected to induce nuclear resonance fluorescence in a predetermined target isotope;
means for conveying material through said bean to produce a transmitted beam, wherein if said material comprises said target isotope, the power of said transmitted beam will be attenuated;
a mono-energetic gamma ray absorption detector configured to detect said reduction in power to identify target material comprising said isotope of interest and to further identity non-target material that does not comprise said isotope of interest; and
a mechanical diverter for separating said target material from said non-target material, wherein said mono-energetic gamma ray source comprises:
an electron source for generating a train of spaced electron bunches;
an RF linear accelerator for accelerating said electron bunches into a laser-electron beam interaction region to produce accelerated electron bunches, wherein the transit time of each of said accelerated electron bunches through said laser-electron beam interaction region is both greater than the duration of said accelerated electron bunch and greater than the spacing between said spaced electron bunches; and
a laser system tor producing a laser pulse having a duration at least as long as a transit time of said laser pulse through said laser-electron beam interaction region, wherein said laser system is arranged so that said laser pulse traverses said laser-electron beam interaction region to interact with all of said accelerated electron bunches and thereby produce said beam of monoenergetic gamma-rays.
11. The apparatus of claim 10 , wherein said duration of said laser pulse is substantially equal to at least a total length of said train of spaced electron bunches so that a single pass of said laser pulse through the laser-electron beam interaction region interacts with all of the accelerated electron hunches of said train.
12. The apparatus of claim 10 , wherein said duration of said laser pulse is substantially equal to a sub-multiple of a total length of said train of spaced electron bunches and said laser system is arranged to recirculate said laser pulse through said laser-electron beam interaction region for a predetermined number of passes equal to an inverse of said sub-multiple.
13. The apparatus of claim 10 , wherein the spacing frequency of said electron bunches is the same as or correlated to the RF frequency of said RF linear accelerator so that an electron bunch is present for every cycle of the RF frequency.
14. The apparatus of claim 10 , wherein said gamma-rays comprise a fractional bandwidth of 10E-3 or less.
15. An apparatus, comprising:
a mono-energetic gamma ray source adapted to produce a beam of mono-energetic gamma rays of a predetermined energy level selected to induce nuclear resonance fluorescence in a predetermined target isotope;
means for conveying material through said beam to produce a transmitted beam, wherein if said material comprises said target isotope, the power of said transmitted beam will be attenuated;
a mono-energetic gamma ray absorption detector configured to detect said reduction in power to identify target material comprising said isotope of interest and to further identity non-target material that does not comprise said isotope of interest; and
a mechanical diverter for separating said target material from said non-target material, wherein the step of detecting is carried out with a detector comprising:
a first structure;
a first integrating detector operatively positioned to detect a signal A from said first structure;
a second structure; and
a second integrating detector operatively positioned to detect a signal B from said second structure, wherein said first structure and said second structure comprise the same atomic material, wherein said first structure comprises a portion A that consist essentially of a first isotope, wherein said second structure comprises a portion B that consists essentially of a second isotope, wherein said first structure and said second structure are configured to intercept at least some portion of beam of monoenergetic gamma-rays.
16. The apparatus of claim 15 , wherein said first structure comprises a first foil and wherein said second structure comprises a second foil.
17. The apparatus of claim 15 , wherein said first isotope consists of U 235 and wherein said second isotope consists of U 238 .
18. The apparatus of claim 15 , wherein said first isotope consists of PU 241 and wherein said second isotope consists of PU 239 .