Beam cooling experiment at ion storage ring, S-LSR

Shirai, Toshiyuki*; Tanabe, Mikio*; Soda, Hikaru*; Ikegami, Masahiro*; Fujimoto, Shinji*; Tongu, Hiromu*; Noda, Akira*; Noda, Koji*; Shibuya, Shinji*; Fujimoto, Tetsuya*; Iwata, Soma*; Okamoto, Hiromi*; Yuri, Yosuke; Grieser, M.*; Fadil, H.*; Syresin, E.*; Seleznev, I. A.*; Smirnov, A.*; Meshkov, I.*

The ion storage ring, S-LSR has an electron beam cooler and a laser cooling system. The electron cooler for S-LSR was designed to maximize the effective cooling length in the limited drift space of the ring. Various experiments have been carried out using the electron beam cooling, such as the sweep electron cooling, the one-dimensional ordering experiment of protons, and the short bunch generation. The laser cooling experiment is also currently in progress. Concerning the one-dimensional ordering experiment, the first proton ordering was successfully confirmed. An abrupt drop in the momentum spread and the Schottky noise power have been observed at the proton number of 2000 with electron currents of 25 mA. The transition temperature of the proton ordering is 0.17 meV in the longitudinal direction.