کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1833080 | 1526501 | 2006 | 9 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Development of a high-efficiency pulsed slow positron beam for measurements with orthopositronium in vacuum Development of a high-efficiency pulsed slow positron beam for measurements with orthopositronium in vacuum](/preview/png/1833080.png)
We have developed a high-efficiency pulsed slow positron beam for experiments with orthopositronium in vacuum. The new pulsing scheme is based on a double-gap coaxial buncher powered by an RF pulse of appropriate shape. The modulation of the positron velocity in the two gaps is used to adjust their time-of-flight to a target. This pulsing scheme allows to minimize non-linear aberrations in the bunching process and to efficiently compress positron pulses with an initial pulse duration ranging from ∼300∼300 to 50 ns into bunches of 2.3 to 0.4 ns width, respectively, with a repetition period of 1μs. The compression ratio achieved is ≃100≃100, which is a factor 5 better than has been previously obtained with slow positron beams based on a single buncher. Requirements on the degree, to which the moderated positrons should be mono-energetic and on the precision of the waveform generation are presented. Possible applications of the new pulsed positron beam for measurements of thin films are discussed.
Journal: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment - Volume 560, Issue 2, 10 May 2006, Pages 224–232