LHC BEAM IMPACT ON MATERIALS CONSIDERING THE TIME STRUCTURE OF THE BEAM

In this paper we report numerical simulations of the ther- modynamic and the hydrodynamic response of a solid car- bon cylindrical target that receives the full impact of the 7 TeV/c LHC proton beam. The calculations have been done in two steps. First, the energy loss of the protons is calculated using the FLUKA code assuming solid mate- rial density. Second, this energy loss data is used as input to a two–dimensional hydrodynamic code, BIG2, to sim- ulate the hydrodynamic effects. As the material is heated due to the energy deposition, hydrodynamic motion sets in that modifies the density distribution in the absorption re- gion. This modified density distribution is then used in the FLUKA code to calculate the corresponding energy loss distribution. The new energy loss data is again used in the BIG2 code and the two codes are thus run iteratively with an iteration interval of 2.5 μs. These simulations have shown that as the target density decreases substantially due to the hydrodynamic motion, the protons that are deliv- ered in the subsequent bunches penetrate deeper into the target, thereby increasing the proton range significantly. It has been found that using this dynamic model, the LHC protons penetrate up to 25 m in solid carbon whereas the corresponding static range of the protons and the shower in solid carbon is about 3.5 m.