| 摘要 |
Disclosed is a method and apparatus for enhancing the brightness of both continuous and pulsed positron beams. By subjecting positrons to non-conservative forces in an interaction region, typically by means of a positron moderator such as a single crystal Cu(111)+S moderator, it is possible to circumvent the limitation, expressed in Liouville's theorem, of the optimally achievable brightness of a beam. The inventive method can be applied in successive stages involving accelerating and focusing a moderated positron beam, and moderating the energetic positrons to thermal energies, resulting typically in an increase in brightness by a factor of about 100 per stage, with an attendant reduction of flux by about factors of ten or less.
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