Proton linac development for neutron science project

The high intensity proton linear accelerator with an energy about 1 GeV and a beam power of several MW has been proposed for the Neutron Science Project (NSP) at JAERI. The objective of the NSP is to explore technologies for accelerator driven radioactive nuclear waste transmutation based on proton induced spallation neutrons as a part of the nation-wide project called the OMEGA (Option Making Extra Gains of Actinides and Fission Products). In the NSP, the linac will also serve as an injector for higher energy accelerators (storage ring/synchrotron) which are used for basic sciences such as neutron scattering research for biology and material sciences and nuclear/particle physics based on a high intensity spallation reactions. Marked characteristics of the accelerator system is to use a superconducting (SC) linac in the high energy part above several hundred MeV. The SC linac is expected to have various favorable characteristics for the engineering purposes such as short length, large bore radius resulting in low beam losses and cost effectiveness for high intensity operation. On the other hand in Japan, the Japan Hadron Project (JHP) has been the long standing next accelerator project at KEK (High Energy Accelerator Research Organization) to promote hadronic sciences. Because both projects have one common feature, high intensity proton linac, the Joint Project between JAERI and KEK has been proposed since 1998. In this paper, however, the only R and D work related to the NSP accelerator will be presented because the detailed accelerator parameters for the Joint Project are still under discussion. (author)