Production of short-pulsed beam for ion-beam pulse radiolysis

Toward the study of the free-radicals behavior, we have proposed a production method of a short-pulsed beam, based on a bunch rotation after momentum cooling. The method was experimentally investigated at the HIMAC synchrotron. In the experiment, after the momentum spread was cooled down to around 0.02% at FWHM through electron cooling, an RF-field was non-adiabatically applied. Under an intensity of (3-7)E6 argon-ions and an RF amplitude of 340 V, a short-pulsed beam with the duration of 30-35 ns at FWHM was obtained after a quarter period of the synchrotron oscillation

Electron cooling of bunched ion beam at NIRS-HIMAC

Electron-cooling experiments have been carried out at the HIMAC-synchrotron in order to provide high-quality beams for medical and related research.For investigating the behavior of the free radicals,especially,the beam bunch was compressed by electron cooling with a triangle-wave RF-field.The dependences of the bunch length on the electron energy and the RF voltage were investigated under various intensities of Ar18+ beam. As a result,the bunch length was limited by around 20 ns due to the space-charge effect under an intensity of 1.33E+6 ions/bunch and an RF amplitude of 340 V