Claims
- 1. A positron beam producing apparatus comprising:
a vacuum chamber; a source of positrons contained in said vacuum chamber, means for forming and containing a positron cloud; means for compressing of said positron cloud; means for extracting a thin positron beam which is emitted from said cloud and is smaller in cross-sectional area than said cloud; means for focusing of said positron beam to a small area; transmitting of said positron beam to said means for focusing; and transmitting of said positron beam onto a target with said small area contacting the target, whereby the interaction of the positrons with said target causes gamma rays and/or particles to be emitted which can be used to provide certain information for analyzing properties of the target.
- 2. The positron beam producing apparatus as defined in claim 1 wherein:
said vacuum chamber contains a quantity of a gas to cool the positrons.
- 3. The positron beam producing apparatus as defined in claim 1 wherein:
said means for focusing comprising an electrostatic lens assembly, said electrostatic lens assembly includes an annular electromagnet which creates an axial magnetic field that terminates at an outer end, said outer end overlapping with an electrode of said electrostatic lens so that the magnetic field of said annular electromagnet decreases to zero rapidly within the length of said electrode.
- 4. The positron beam producing apparatus as defined in claim 1 wherein:
said means for compressing comprises a series of annular electrodes located axially each of which having a through opening through which said positrons are to be passed.
- 5. The positron beam producing apparatus as defined in claim 4 wherein:
one of said series of said annular electrodes comprising an annular array of electrode segments, said annular array of electrode segments are subjected to sequential activation producing a rotating electric field.
- 6. The positron beam producing apparatus as defined in claim 1 wherein:
said means for compressing of said positron cloud comprises a series of Penning Traps.
- 7. The positron beam producing apparatus as defined in claim 1 wherein:
a vacuum pumping restriction is provided between the positron cloud and said means for focusing.
- 8. The positron beam producing apparatus as defined in claim 1 wherein:
the means for focusing of said positron beam is controlled to maintain a small beam area on the target as positrons are extracted from different radii within the positron cloud.
- 9. A method for compressing a positron cloud producing a thin positron beam which is to be transmitted to a solid for the purpose of analyzing properties of the solid comprising the steps of:
supplying a source of positrons within a vacuum environment; forming and containing a positron cloud; subjecting said positron cloud to electric and magnetic fields to compress the positron cloud; extracting a positron beam from said positron cloud; focusing of said positron beam producing a focused beam; and transmitting of the focused beam onto said solid.
- 10. The method as defined in claim 9 wherein following the supplying step there is included the additional step of:
adding a gas into the vacuum environment to cool the positrons.
- 11. The method as defined in claim 9 wherein:
the subjecting step also includes the additional step of extracting a thin positron beam from said cloud wherein said positron beam is smaller in cross-sectional area than said cloud.
- 12. The method as defined in claim 9 wherein:
said compressing step includes using of a rotating electric field.
- 13. The method as defined in claim 9 wherein:
the focusing step includes using a vacuum pumping restriction prior to said focusing step.
GOVERNMENT CONTRACT INFORMATION
[0001] This invention was made with U.S. Government support under Contract No. N00014-00-C-0710 awarded by the Office of Naval Research. The Government has certain rights in this invention.
Provisional Applications (1)
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Number |
Date |
Country |
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60222309 |
Aug 2000 |
US |