Electrostatic separator for K1.8 beam line at J-PARC

The new electrostatic (ES) separator to select and deliver 1-2 GeV/c kaon beams is made for the secondary beam line at the high intensity proton accelerator facility. The ES separator will generate a 75 kV/cm electrostatic field between parallel electrodes of 10 cm gap and 6 m in length along the beam direction. The K−/π− ratio of the line is expected to have a larger value than 1. It is designed so as to be radiation-proof and to lower spark rate comparing with the present separators.