Review
Feasibility Study on Laser Stripping Injection for J-PARC RCS
2016 Volume 13 Issue 2 Pages 80-90
Details
2016 Volume 13 Issue 2 Pages 80-90
Feasibility is studied on the laser stripping injection of H⁻ beam for J-PARC RCS. The injection energy is 400 MeV and the repetition frequency of H⁻ micro-bunch is 324 MHz. Major hurdles to be cleared are as follows. Because necessary magnetic field for the Lorentz stripping of H⁻ ion and the 2nd excited state of H⁰ atom is no less than about 2 T and too high to install in the injection area. Therefore, photo-detachment using Nd:YAG laser is to be adopted. Because the Doppler effect is weak at 400 MeV, an excimer laser is necessary in order to excite H0 atom from ground state to the 2nd excited state, whose excitation energy is 12.1 eV. Because the momentum spread of the H0 beam is ～10−3, the laser band width in the particle rest frame is broadened by the Doppler effect and the necessary laser-pulse energy is accordingly increased. In order to supply necessary laser-beam pulse in 324 MHz, a laser-storage ring is to be developed.
