[1B06-07] Plasma Science & Technology (PST)

4:15 PM - 4:30 PM JST(7:15 AM - 7:30 AM UTC)

[1B06] Preparation and Performance Evaluation of Sputter-Deposited Yttrium Films for the Stopping and Neutralization of Recoil ²²¹Fr Produced by the Alpha Decay of ²²⁵Ac

*Ryosuke Tsutsui¹, Masaki Nakazawa¹, Yu Nezu³, Shintaro Nagase¹, Naoya Ozawa², Yasuhiro Sakemi¹ (1. The University of Tokyo (Japan), 2. Kyoto University (Japan), 3. Rikkyo University (Japan))

We are developing a ²²¹Fr source for a permanent electric dipole moment measurement. Recoil ²²¹Fr produced by the alpha decay of ²²⁵Ac has an energy of 103 keV and must be supplied as low-energy neutral atoms. To stop and neutralize the recoil Fr, a Y film is sputter-deposited onto a ²²⁵Ac source. The deposited Y layer stops recoil ²²¹Fr, which is subsequently released by heating and is expected to emerge as neutral atoms because of the low work function of Y. We evaluate the stopping performance and neutralization efficiency of the Y film by distinguishing unrecovered recoil Fr, thermally released neutral Fr, and thermally released Fr ions using alpha-particle measurements with a solid-state detector and an ion-attracting electrode. We report the source performance and its dependence on Y film-deposition conditions.

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