Bulk shielding for laser research centre ELI Beamlines

The civil structure for the laser research centre ELI Beamlines has been designed to provide adequate radiation protection for both personnel and the public. The facility will host primary sources of photons, electrons and protons. Pulsed mixed fields of high energy particles (up to several GeV) will be generated, producing up to 10 12 particles of primary radiation, in pulses of several fs length. Shielding calculations were undertaken using Monte Carlo transport codes FLUKA and MCNPX, together with a discrete ordinates code ATTILA. Integration of the Monte Carlo and discrete ordinates methods allowed assessment of complex shielding geometries to proceed faster than could be achieved through the use of either biased or analogue Monte Carlo alone. It was possible to design the building, so that the expected annual dose accrual of workers will be lower than 1 mSv. The main contributors to the total dose are neutrons. Therefore, for penetrations, it is necessary to ensure shielding against neutrons.