Conceptual design of proton beam transport system for ADS facilities at J-PARC

To examine the materials issues related to accelerator-driven systems (ADSs), the Japan Proton Accelerator Research Complex (J-PARC) is planning to build the ADS Target Test Facility (TEF-T). The J-PARC also plans to build a Transmutation Physics Experimental Facility (TEF-P), where a subcritical assembly will be located. A fundamental design study for the proton beam transport system to deliver a proton beam to TEF-T and TEF-P has started. A 0.4 GeV proton beam with a relatively high beam power of 0.25 MW is introduced to a lead-bismuth (LBE) target in the TEF-T, where many species of samples are located, for post-irradiation experimental studies of the materials. In contrast, the beam power for the TEF-P is regulated at a level of several watts to ensure the safety of the subcritical assembly. In this study, feasibility studies of beam transport are performed to further the design of the TEF-T system. To introduce the beam to the LBE target, horizontal and vertical beam injection can be considered. To match the geometrical conditions of the TEF-T, perpendicular beam injection, where the beam is introduced from the bottom of the target, is difficult because of the long drift space required in front of the target for beam expansion. Consequently, horizontal beam injection to the TEF-T is chosen. The beam profile at the target is obtained using a simulation. On the basis of the parameters obtained in this study, the beam facilities of the TEF-T and TEF-P will be constructed in the near future.