Simulation of the losses by decay in the decay ring for the beta-beams

The aim of the 'beta-beams' is to accelerate and store high intensities of highly energetic β radioactive ions until they decay. The problem is that the ions decay during all the acceleration process and the decay products will be lost on the walls of the different machines. The activation must be studied in the whole complex (PS, SPS and the decay ring). However, since the stored intensity is the biggest in the decay ring, its design must take into account the power deposition problem very early. In this note, we focus on the evaluation and the localization of this kind of losses in the decay ring. We see that this determines the bend length. The amount of losses is so high that we have to optimize the design to enable the insertion of beam stoppers in the ring. For the moment, we consider only ⁶He²⁺ because the ¹⁸Ne¹⁰⁺ intensity is one order of magnitude lower. It is not the case if the ¹⁹Ne¹⁰⁺ is chosen instead. In this case, the design will have to be optimized for the deposition of the both species. In order to evaluate our structure, we have written a code which quantifies the depositions in the ring. At the moment, it does not take into account the sextipolar kicks and the interaction with the matter. However, it is quite fast and locates the deposition peaks. We are looking forward to working with ACCSIM to compare with our results