Development of a gas-sheet target for monitoring the high intensity proton beam

Ogiwara, Norio; Hikichi, Yusuke; Kamiya, Junichiro   ; Kinsho, Michikazu  

The 3 GeV Rapid Cycling Synchrotron (RCS) in the Japan Accelerator Research Complex (J-PARC) project is planned to generate a high-power beam of 1 MW. In order to supply continuously the beam of 1 MW it is important to reduce the beam loss thoroughly. Thus the non-disruptive and fast-response beam diagnostic tools for extensive researches have been strongly required. To realize the fast non-disruptive beam profile detection, we intended to apply the molecular beam technique for making the compact and large-scale gas-sheet target. Monte Carlo simulations demonstrate the generation of large-scale gas-sheet targets in a vacuum by a thin concentric slit with a large aperture. Here gas is introduced from the outside toward the center, leading to the appearance of a large-scale gas sheet around the center. With inner and outer diameters of 200 and 400, respectively, and a gap of 0.1, the generated gas sheet had a diameter of 130 and thickness of less than 0.4 (half width), where all the valuables are expressed in ratio.