A Beam Dump Facility (BDF) at CERN – The Concept and a First Radiological Assessment

The Beam Dump Facility (BDF) Project, currently in its design phase, is a proposed general-purpose fixed target facility at CERN, dedicated to the Search for Hidden Particles (SHiP) experiment in its initial phase and whose aim is to fully absorb the high intensity 400 GeV/c SPS beam. The BDF target complex would be located underground at a depth of about 10 m and is designed to contain most of the cascade generated by the primary beam interaction. Due to the high beam intensity delivered on target, the high density and high-Z composition of the target/dump, high activation of the material is expected, therefore evaluation of radiation protection risks is a crucial aspect for the design of this facility. In particular, high prompt and residual dose rates call for considerable shielding and remote interventions in the target area. Also the risk and environmental impact from air, water and soil activation heavily influence the design. In order to respect the applicable CERN radiation protection legislation regarding doses to personnel as well as the environmental impact, a preliminary radiological study was carried out. In order to validate the design of the BDF target, a scaled prototype was tested during 2018 in the SPS North Area at CERN. Preliminary results of radiological aspects for this test will be presented as well. To assess the above-mentioned radiation protection aspects, extensive simulations were performed with the FLUKA Monte Carlo particle transport code.