Ultralow emittance beam production based on Doppler laser cooling and coupling resonance

Noda, Akira*; Nakao, Masao*; Okamoto, Hiromi*; Osaki, Kazuya*; Yuri, Yosuke; Soda, Hikaru*; Tongu, Hiromu*; Jimbo, Koichi*; Grieser, M.*; He, Z.*; Smirnov, A.*

Three-dimensional (3D) cooling of 40-keV Mg ion beams with Doppler laser cooling and the coupling resonance has been demonstrated in the storage ring S-LSR of Kyoto University toward the production of ultralow-emittance beams, in other words, ultracold beams and so-called crystalline beams. So far, the transverse temperatures of 6 K and 2 K have been experimentally attained in the horizontal and vertical directions, respectively, at a low beam intensity of about ions in the ring. These temperatures are the lowest ever attained by laser cooling of ion beams. Systematic molecular dynamics simulations predict the realization of further lower temperatures, 1 mK and 0.1 K in the longitudinal and transverse directions, respectively, if the laser spot size and detuning are properly adjusted even with such a low laser power ( 10 mW) as utilized in the experiments at S-LSR. A 3D ordered state of the beam with 3D laser cooling is also predicted. Recent experimental achievements and latest simulation results are presented.