Grobal spill control in RF-knockout slow-extraction

The time structure of extracted beams has been improved in synchrotron rings with resonant slow-extractionincluding RF-knockout extraction.In order to control the global spill structure in the RF-knockout slow-extractionmethod,it is necessary to improve the amplitude modulation (AM)function of the transverse RF-field.For thispurpose,a scheme with a simple model of the extraction process has been proposed.Using this simple model,ananalysis was carried out for determining the parameter relevant to the diffusion process in the separatrix.With thisparameter,the new AM function obtained by the analytical approach could provide a flat spill within 7 in both asimulation and an experiment at the HIMAC synchrotron.Cooperating with the feedback system,the global spillstructure was signi ficantly suppressed to be less than 7

Design and measurement of the S-LSR quadrupole magnet considering the influence of a neighboring field clamp

The design and the magnetic field measurement of the quadrupole magnet for the compact ion ring, S-LSR, are presented. Because the S-LSR is a compact ring accelerator, whose components take up most of the space in the arc sections. Therefore, we have to optimize the integrated field gradient in the quadrupole magnetic field taking account of the effect of the neighboring field clamp. Under these conditions plus requirements from accelerator parameters, the design of the S-LSR quadrupole magnet was optimized by means of 2D and 3D modeling calculations. A magnet field measurement by a Hall probe is carried out together with the field clamp and S-LSR bending magnet. Both results of the calculation and the measurement present the almost same result as that for the effect of the field clamp

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