Development and Present Status of Ion Storage/Cooler Ring, S–LSR

Abstract

An ion storage and cooler ring, S–LSR has been constructed at Institute for Chemical Research, Kyoto University. Its circumference is 22.57 m and it can accumulate and cool the beams of 7 MeV proton, 40 keV ²⁴Mg⁺ and 2 MeV/u¹² C⁶⁺ ions. Electron cooling of hot ions by sweeping the relative velocity between the electron and ion beams has been experimentally demonstrated and the cooling time has been almost one order of magnitude reduced with such a scheme. Lowest temperature limit of electron cooled 7 MeV protons has also been studied reducing the particle number. Sudden jump of momentum spread corresponding to one dimensional phase transition to the ordered state has been observed at ～2000 particles for the first time for proton beam. One dimensional laser cooling of ²⁴Mg⁺ has also been realized with and without application of induction acceleration. Creation of three dimensional crystal beam is our next goal with the use of three dimensional laser cooling taking the suppression of shear into account.