Design of a compact electron cooler for the S-LSR

The Small Laser-equipped Storage Ring (S-LSR) project has been initiated by ICR of Kyoto University and NIRS, with the purpose of demonstrating the feasibility of electron beam cooling of laser produced ions. A compact electron cooling device with a cooling solenoid length of 0.8 m and two 90° angle toroid magnets of radius 0.25 m will be installed in the S-LSR, which is required to reduce the velocity spread of a laser induced carbon ion beam with a mean energy of 2 MeV/u from 1% to 0.1%. The magnetic field of the main solenoid is 500 G, and the maximum expansion factor is 3. The design of this electron cooler is presented.