Author/Authors :
Sakaguchi، نويسنده , , J. and Gilg، نويسنده , , H. and Hayano، نويسنده , , R.S and Ishikawa، نويسنده , , T. and Suzuki، نويسنده , , K. and Widmann، نويسنده , , E. and Yamaguchi، نويسنده , , H. and Caspers، نويسنده , , F. and Eades، نويسنده , , J. and Hori، نويسنده , , M. and Barna، نويسنده , , D. and Horvلth، نويسنده , , D. and Juhلsz، نويسنده , , B. and Torii، نويسنده , , H.A. and Yamazaki، نويسنده , , T.، نويسنده ,
Abstract :
For the precise measurement of the hyperfine structure of antiprotonic helium, microwave radiation of 12.9 GHz frequency is needed, tunable over ± 100 MHz . A cylindrical microwave cavity is used whose front and rear faces are meshed to allow the antiprotons and laser beams to enter. The cavity is embedded in a cryogenic helium gas target. Frequency tuning of ∼ 300 MHz with Q values of 2700–3000 was achieved using over-coupling and an external triple stub tuner. We also present Monte-Carlo simulations of the stopping distribution of antiprotons in the low-density helium gas using the GEANT4 package with modified energy loss routines.
