FAIR Newsletter No. 12 - GSI Webserver WWW-WIN

Status of FAIR Radiation Safety
Georg Fehrenbacher (GSI)
FAIR Newsletter No. 12 April 2009
Radioactive Activation of Components at FAIR
The operation of the FAIR heavy ion accelerators will be associated with the
production of short-lived radioactivity. Two main paths dominate this: The
fragmentation of projectile and target nuclei and the causation of spallation reactions
by high energy neutrons, being released in heavy ion nuclear reactions.
Fig. 1: Shielding design and dose distribution in the target area of the Super-FRS and in the
maintenance channel.
In the framework of two research projects, SAFERIB (EURONS contract 506065)
and GSI-INTAS (EU-contract 03-54-3588), the production of radioisotopes was
measured and calculated. Measurements for uranium beams were performed at GSI
at energies of 500 and 950 MeV/u, Copper and stainless steel were chosen as targets.
The experiment was modeled using the FLUKA 1 Monte Carlo (MC) code. The key
results of the measurements can be summarized as follows: The overall production of
radioactivity can be estimated with FLUKA within a factor of two, and the magnitude
of the activity of the produced radioisotopes is dominated by target fragmentation 2 .
The building up of radioactivity and the exposure of personnel to potential radiation in
specific experiment and accelerator structures can be estimated on the basis of MC
computations and on assumptions for operation modes and beam parameters.
Refining of layouts of such areas improve the radiological circumstances.
The target area of the Super Fragment Separator (Super-FRS) is an example for
the development of a shielding layout for an area with radioactivity production.
1 FLUKA: a multi-particle transport code" G. Battistoni, S. Muraro, P.R. Sala, F. Cerutti, A. Ferrari, S. Roesler, A.
Fasso`, J. Ranft, Proceedings of the Hadronic Shower Simulation Workshop 2006, Fermilab 6--8 September 2006, M.
Albrow, R. Raja eds., AIP Conference Proceeding 896, 31-49, (2007) "The FLUKA code: Description and
benchmarking" A. Fasso`, A. Ferrari, J. Ranft, and P.R. Sala, CERN-2005-10 (2005), INFN/TC_05/11, SLAC-R-773
2 E. Kozlova et al. Validation of the FLUKA MC code for residual production with 500 MeV/u and 950 MeV/u
Uranium Beam on Copper and Stainless Steel Target, ICRS11, Georgia, USA (2008) accepted for publication in
Nuclear technology (2009)
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