Evaluation for suppression method of emittance growth due to space-charge effect in J-PARC Linac

Chimura, Motoki; Harada, Hiroyuki ; Moriya, Katsuhiro ; Okabe, Kota ; Kinsho, Michikazu 

Beam intensity in a high-intensity proton accelerator is an important parameter in user experimental facilities. Beam emittance growth and beam loss due to space charge effect make a limit of beam power from the view point of high activation at devices. In order to identify the source of beam emittance growth due to space charge effect, we performed beam simulation by using a model of J-PARC Linac. As the result, nonlinear component of space charge force causes a strain of beam distribution and emittance growth. We proposed a new method for suppression of the nonlinear component by using multipole magnet and simulated the method in our model. As the result, we indicated that the growth is suppressed by using the nonlinear field. In my presentation, we report the new method and simulation results.