International Topical Meeting on Nuclear Research Applications and Utilization of Accelerators

4-8 May 2009, Vienna

Lay-out of the EURISOL Experimental Hall

D. Ene, J.C. David, D. Doré, and D. Ridikas

CEA, Saclay, IRFU, SPhN, Gif-sur-Yvette, France

Corresponding Author: daniela.ene@cea.fr

The EURISOL project is aimed at the design of the next generation European ISOL radioactive ion beam (RIB) facility able to deliver high intensity beams of 10¹³ pps at energy up to 150 MeV u^-1. The RIBs of 21 MeV u^-1 and 150 MeV u^-1 will be extracted to a number of experimental halls, 99 where they interact with secondary targets. The purpose of this study is to configure the shielding and the management of the access to the controlled areas inside the beam experimental halls. In agreement with physics case of the project it was decided to investigate six target materials: CH₂, Be, C, Cu, Ni and Pb at two possible thicknesses of 1 mg cm^-2 and 10 mg cm². The experimental hall hosting the AGATA germanium array detector was selected as the conservative case. The conceptual model for the beam dump system to be placed at the end of the post-accelerator beam line, whose feasibility was previously demonstrated, was used here also to examine safe operation conditions inside the experimental hall. Therefore the geometry model used in simulations contains:

• a simplified AGATA detector placed in the centre,
• a typical experimental target positioned inside AGATA, and
• a V-shaped beam dump configuration with a water-cooled graphite core and a subsequent iron block downstream of the beam line. A test case of ¹³²Sn²⁵+ RIB was used in simulations.

Neutron production yields from the physics targets, dose rate estimates in the experimental area and behind the shielding walls and energy deposition on the beam dump were calculated and analysed in this study. Dedicated simulations were performed by means of the PHITS Monte Carlo computer code. In order to characterise the residual radiation environment inside the experimental halls the following procedure was developed. Induced radioactivity in the targets, AGATA equipment, concrete wall and the air inside were estimated using DCHAIN–SP–2001 code. Ambient dose equivalent rates due to the residual radiation were calculated with the MCNPX code using photon sources resulted from DCHAIN activation calculations. The lay-out of the experimental area was schematically configured by preliminary sizing of concrete shielding walls. The paper provides also the magnitude of the radioactive material inventory generated inside this zone and the associate dose rate estimates.