Shielding of the Target Area of the Fragment Separator Super-FRS

The Super-FRS is designed as a versatile partially superconducting fragment separator for the planned international Facility for Antiprotons and Ion Research. It will be able to separate all kinds of nuclear projectile fragments of primary heavy-ion beams including uranium with energies of up to 1.5 GeV/u and intensities of up to 10¹² particles/s. The primary beam power of up to 50 kW has to be dumped in six shaped beam catchers in accordance with the ion optical setting of the separator in order not to enter the main separator, which will have accordingly weaker shielding. A key issue for such a high-power facility is the activation of several components and thus their access by maintenance personnel. Both the prompt and the residual dose due to activation are calculated by means of the Monte Carlo particle transport code FLUKA.

The biological shielding in the target area will be realized by massive iron blocks (thickness [approximate] 2 m) around the beam tube and the magnets. This will be surrounded by up to 6 m of concrete in order to reduce the dose rates below the design value of 0.5 Sv/h, which is in agreement with the German radiation protection ordinance for public access. A dedicated maintenance channel is foreseen in which the residual dose rates are tolerable for short time access after a certain cooling time.