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

ALTERNATING-PHASE-FOCUSED IH-DTL FOR HEAVY-ION MEDICAL ACCELERATORS

Compact linacs, consisted of a Radio-Frequency- Quadrupole (RFQ) linac and Interdigital H-mode Drift- Tube-Linac (IH-DTL) having the same operating frequency of 200 MHz, were designed for an injector ofheavy-ion medical accelerators. For beam focusing of IH-DTL, the method of Alternating-Phase-Focusing (APF) was applied. The total length of the RFQ linac and APF IH-DTL is approximately 6 m. With the two linacs, carbon ions produced by an ECR Ion-Source (ECRIS) could be accelerated up to 4.0 MeV/u. The compact linacs were constructed and installed in NIRS. We have succeeded to accelerate carbon ions with the APF linac for the first time. The present status of the compact linacs as well as results of acceleration tests was presented