A rectifying tungsten-molybdenum foil for positron remoderation
作者:
L. V. Jo&slash;rgensen,
A. van Veen,
H. Schut,
J. Chevallier,
期刊:
Journal of Applied Physics
(AIP Available online 1997)
卷期:
Volume 81,
issue 6
页码: 2725-2729
ISSN:0021-8979
年代: 1997
DOI:10.1063/1.363975
出版商: AIP
数据来源: AIP
摘要:
We report the use of a layered foil as a positron rectifying device for transmission geometry positron moderation and remoderation, thereby increasing the efficiency of such devices. Positron transmission through foils consisting of a 10 nm W layer on top of a 100 nm Mo foil has been measured. The measurements are compared with similar results for a 100 nm W foil. A strong rectifying effect with a forward to reverse current ratio of more than 10 is observed making this type of well matched layered foils an obvious candidate for positron remoderation. Retarding energy spectra of the transmitted positrons were obtained and measurements of Doppler broadening and surface branching ratios were performed to further characterize the foils. The obtained transmission results again reveal the discrepancy in positron implantation profiles for thin foils between experiments and existing theory. ©1997 American Institute of Physics.
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