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JJAP Conference Proceedings

JJAP Conf. Proc. 2, 011004 (2014) doi:10.7567/JJAPCP.2.011004

Energy loss of positrons below the excitation threshold in Ar gas

Yosuke Sano1, Yasushi Kino1, Toshitaka Oka1,2, Tsutomu Sekine2

  1. 1Department of Chemistry, Tohoku University, Sendai 980-8578, Japan
  2. 2Institute for Excellence in Higher Education, Tohoku University, Sendai 980-8576, Japan
  • Received May 31, 2014
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We performed positron age-momentumcorrelation measurements to investigate the positron slowing down process in Ar gas at 7.5 MPa. Increase in the S parameter was observed up to 1 ns, and then stayed on the same level. By comparing with the calculated energy loss of positrons via elastic scattering, it was concluded that the increase in the S parameter corresponded to the positron slowing down from 11.6 eV to 2.5 eV. The positron slowing down process just below the first electronic excitation energy of Ar gas can be observed using the S parameter.

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