Thermal analysis of the injection beam dump of 3 GeV rapid cycling synchrotron

In the High-Intensity Proton Accelerator Project, an injection beam dump of the 3 GeV rapid cycling synchrotron (3 GeV-RCS) is to be installed to absorb small amount of H- and H0 beams that can not be changed into H+ beam with a graphite foil. The beam power absorbed in the dump would become up to 1kW. From the viewpoint of feasibility of the beam dump, it is necessary to estimate the maximum temperature and thermal stress caused by the absorbed beam power. Thermal analyses were carried out to clarify the temperature and thermal stress distributions in the dump including concrete walls by using the ANSYS code, which were based on the heat deposition rates obtained with the MARS code. Analytical results showed that the temperature at the center region made of iron reached up to 370 K after several operation cycles (one cycle is three-week operation including one-week interval) under the 1kW-beam injection. Then, the temperature at the boundary between the iron region of the beam dump and the concrete wall of the tunnel was rather low temperature of about 320 K, which was lower than the allowable temperature of the concrete. Also, the maximum Mises stresses of 96 MPa and about 0.2 MPa were generated in the iron region and the concrete wall respectively, which were much lower than the allowable stresses of iron and concrete. (author)