Evaluation of 2-D transverse beam profile monitor using gas sheet at J-PARC LINAC

Kamiya, Junichiro   ; Okabe, Kota  ; Kinsho, Michikazu  ; Moriya, Katsuhiro  ; Yamada, Ippei; Ogiwara, Norio*; Hikichi, Yusuke*; Wada, K.*

To obtain a getter effect to titanium vacuum duct surface, the method to remove the oxide on the surface by sputtering with ionized molecules has been developed. In the method, a sheet-shaped gas distribution with a uniform and high density is generated through a narrow slit by a small amount of gas. In this report, the gas density distribution was calculated by the Monte Carlo simulation code. As a result, it was found that a gas injection from both directions was effective to generate uniform density distribution. Furthermore, the gas injection method was applied to a non-destructive beam profile monitor, that detects ions generated by the interaction between gas molecules and beam. In this monitor, dependence of the beam profile on the injected gas amount was measured. A small amount of injected gas was found to be ideal for the beam profile measurements in the unsaturated and a high S/N ratio region.