Preliminary evaluation of beam dump for high current electron beam at JNC Original Research Article

A high current electron beam is required for transmuting fission products using gamma rays. Elemental technology for a linac that generates a high current beam in an efficient and stable manner is being developed at Japan Nuclear Cycle Development Institute (JNC). A beam dump for the high current, low energy electron beam (20 mA, 10 MeV) from this accelerator has been constructed and tested at JNC. A Ring and Disk (RD) structure was adopted to absorb the beam safely and to analyze the beam condition in real time. The thermal and stress analysis showed that a 200 kW electron beam could be securely stopped. The performance of the beam dump was evaluated using a beam of 7.0 MeV and an average current of 0.84 mA. The measured results showed that the electrons transported from the accelerator were completely absorbed. The temperature rise of the plates and the 1 cm dose equivalent rate of bremsstrahlung photons were consistent with the simulation data. In addition, the beam dump was found to be capable of monitoring the beam condition directly from the temperature distributions and peak current.