Shielding calculations for the design of new beamlines at ALBA synchrotron

Abstract

ALBA is a Spanish synchrotron facility generating intense beams of synchrotron radiation from a 3 GeV electron accelerator. At ALBA Synchrotron, electrons are first accelerated in a 110 MeV linear accelerator and then injected in Booster ring which increases the energy up to 3 GeV. Finally, the electron beam is stored in a synchrotron Storage Ring with a current up to 400 mA emitting intense beam of synchrotron radiation. Both the Booster and the Storage Ring are located inside the same concrete building, the Tunnel, while the LINAC is located in a separated concrete building, the Bunker. Outside the Tunnel, and tangentially to the Storage Ring, are located the experimental research laboratories, the Beamlines, where scientists receive synchrotron light for a wide variety of experiments. At present ALBA has 8 Beamlines installed, 3 Beamline under construction, and 1 Beamlines in the design stage.This paper details the design of the shielding elements of the new Beamlines under construction called LOREA, NOTOS and XAIRA. The first one is a soft X-ray and the other two are hard X-ray Beamlines. Shielding calculations are performed using FLUKA Monte Carlo code and aim at quantifying the total dose rate produced by the different sources of radiation at the Beamlines in operation. In particular, it details the dose generated by the gas bremsstrahlung radiation resulting from the interaction of the 3 GeV electron beam with the residual gas of the storage ring vacuum chamber and compares it to the dose rate generated by the insertion device radiation flux. The objective of the FLUKA simulations performed in this work is to establish the requirements for all the Beamline shielding elements to ensure a public dose (dose rate lower than 0.5 μSv/h) outside the shielding during Beamline operation. Results from the simulations set the general requirements for all the Beamline shielding elements, from a radiation protection point of view.