Acceleration of Heavy-Ion Beams at J-PARC

In the development of nuclear physics in Japan, research using so-called high-energy heavy ion beams of 10 GeV per nucleon or more has been a research vacuum due to the lack of facilities in Japan to accelerate such beams and conduct experiments.

The only realistic possibility to overcome this situation is to accelerate heavy ions using J-PARC, which can accelerate protons up to 30 (50) GeV. J-PARC consists of a 400 MeV proton linear accelerator (LINAC), a 3 GeV Rapid Cycling Synchrotron (RCS), and a 30 (50) GeV Main Synchrotron (MR). Unfortunately, the LINAC cannot accelerate heavy ions, so a separate heavy ion accelerator must be prepared to inject heavy ions into the RCS.

Therefore, we came up with the idea of reusing the KEK-PS-500MeV-booster accelerator, which had been accelerating protons up to 500 MeV in the KEK-12GeV proton synchrotron, which has already been shut down, as a realistic option to realize a heavy ion injector at relatively low cost and in a short time.

This accelerator is stored in working condition at KEK Tsukuba and can be combined with an appropriate injector (e.g., a linear accelerator that can accelerate heavy ion beams up to several MeV/u) to realize a heavy ion injector for the RCS.

In this presentation, a scheme for heavy-ion acceleration that can be realized at J-PARC at an early stage will be presented, together with some first experimental design proposals.