Feasibility studies of a vibration wire monitor and a halo scraper in the J-PARC L3BT

In the Japan Proton Accelerator Research Complex (J-PARC) 3-GeV rapid cycle synchrotron (RCS), transverse beam halo diagnostics and scraping are required to increase the output beam power. Wire scanners and halo scrapers were used to measure the projected beam distributions to determine the extent of beam halo formation at the linac 3-GeV beam transport line (L3BT). In order to determine more details of halo formation, we installed a vibration wire monitor (VWM) in the L3BT for the beam halo measurement. The high sensitivity of the VWM makes it a prospective tool for investigating the beam halo and weak beam scanning. Also, we developed a new vertical scraper system with a thin carbon foil to collimate the beam halo in the L3BT. In this paper, we will report a preliminary result for the beam-halo measurement by using a VWM and a halo scraper at the L3BT, and we will discuss the potential of the VWM for beam-halo diagnostics.