Twiss parameter matching of the injection beam for the J-PARC RCS

Okabe, Kota  ; Maruta, Tomofumi*; Hotchi, Hideaki  ; Saha, P. K.   ; Yoshimoto, Masahiro  ; Miura, Akihiko ; Liu, Y.*; Kinsho, Michikazu  

In a high power proton accelerator such as the 3-GeV rapid cycle synchrotron (RCS), small ratio of the beam loss such as beam halo can cause serious radiation dose. The suppression of the transverse beam halo is a key issue to provide high intensity beam for routine user operation at the RCS. If the transverse twiss parameter of the injection beam is not matched to the RCS optics, it will generates beam halo during the multi-turn injection. In order to suppress such beam halo, twiss parameters and dispersion matching are performed at the RCS injection point. In the beam matching process, we use the rms envelope equation solver with space charge effect to predict high intensity beam behavior. The beam profile measurement is done with wire scanner monitors at the downstream of the L3BT as well as multi-wire profile monitors at the RCS injection section. In this presentation, we introduce the transverse twiss parameter matching scheme at the RCS injection points.