Non-Destructive 2-D Beam Profile Monitor with a Sheet-Shaped Gas

Abstract

A non-destructive beam profile monitor with a sheet-shaped gas has been developed. The gas sheet formed based on rarefied gas dynamics produces photons by interaction with a high intensity ion beam. The sheet shape enables a two-dimensional profile measurement by CCD camera capture of the photons. The beam profile can be obtained from the captured image through a reconstruction analysis with a response function of the monitor. The response function was measured by scanning of a thin electron beam on the monitor. The developed monitor was evaluated with the RFQ test stand consisting of J-PARC linac spares, and a 2-D high-intensity-beam profile was successfully reconstructed. The non-destructiveness of the developed monitor was also evaluated in terms of a beam current reduction and a beam phase space distribution change. The beam current reduction was in proportion to the injected gas flux, and the emittance decreased at high gas flux injection.