Slowing-down of relativistic heavy ions and its influence on angular distributions of Vavilov–Cherenkov radiation

We performed calculations of Vavilov–Cherenkov radiation (VChR) angular distributions from relativistic heavy ions (RHI) taking account of their slowing-down in a radiator. The results of calculations show that the slowing-down of RHI in radiator leads to specific broadening of VChR ring thus forming specific VChR angular distribution which is different compared to well-known Tamm–Frank distribution. The key parameters which change drastically the VChR angular distribution from RHI are: energy, charge and mass of an ion; emission wave length and corresponding refractive index; stopping power and radiator thickness. The theory developed has been applied to the analysis of the earlier experiments (1996–2001) devoted to studies of the VChR angular distribution from Au RHI beam with energies ∼0.9 GeV/u at SIS-18 heavy ion accelerator (GSI, Darmstadt, Germany)