Radiation and shielding design on the simplified experimental muon source at CSNS

Abstract

BackgroundChina Spallation Neutron Source (CSNS) based on the spallation reaction is a large multidisciplinary research facility, which has been constructed and commissioned since August 2018. Experimental Muon Source (EMuS) is one of the important research platforms for the future construction of CSNS. The proton beam energy is 1.6 GeV and the power on the carbon target is 20 kW.PurposeThis study aim to design radiation and shielding system for EMuS that satisfies the requirements of radiation safety.MethodsThe Monte Carlo simulator of FLUKA was used to calculate and analyze the prompt radiation and residual radiation. According to the dose limit, the shielding optimization design was carried out, and abandoned proton beam flux was estimated. Finally, computational results of FLUKA were analyzed, and compared with that of the Moyer mode semi-empirical formula.ResultsThe simulation results show that the exterior residual radiations of shielding for the high radiation area such as target area, collimation area, dump and muon transport line are very low whilst the inside components such as carbon target, magnets, and vacuum pipes of high-energy proton transport line are critically activated and have high residual radiation. The abandoned proton beam after carbon target is of 1012 cm-2∙s-1.ConclusionsThe optimal shielding design meets the requirements of prompt radiation protection for EMuS of CSNS, but the strategy of remote operations and strict control of maintenance time need to consider for the future maintenance and upgrade. Abandoned proton beam can be efficiently utilized to build a proton irradiation platform and a neutron irradiation platform with carefully studying of the background of those irradiation points.

Keywords

• high-energy proton beam
• prompt radiation
• residual radiation
• shielding
• moyer model
• irradiation platform