Beam halo measurement using a combination of a wire scanner type beam scraper and some beam loss monitors in J-PARC 3-GeV RCS

Yoshimoto, Masahiro  ; Harada, Hiroyuki  ; Okabe, Kota  ; Kinsho, Michikazu  

Transverse beam halo is one of the most important beam parameters due to limit the performance of the high intensity beam accelerator. Therefore the transverse beam halo measurement is required to increase the beam power of the J-PARC 3-GeV RCS. In the beam profile, there are the beam core which is a high density area, the beam tail which is a low density area around the beam core, and the beam halo which is the area outside of the beam tail and in which few particles are straggling. Generally, the beam halo intensity is less than 1/100000 1/1000000 of the beam core. Therefore, the dynamic range of the beam halo is required typically an order of 10, but it is difficult to achieve this ultra wide dynamic range by any one diagnostics. Then, new beam halo monitor, which is combined a wire type beam scraper and some beam loss monitors, are developed and installed in the extraction beam transport line. Each beam loss monitor has not more than 10 order of the dynamic range. However, to use some beam loss monitors with a plurality of different sensitivity range, its ultra wide dynamic range can be achieved and beam profile including both of the beam core, beam tail, and beam halo can be obtained.