Energy losses of 252Cf fission fragments in thin foils

The stopping power of fission fragments from 252Cf(sf) has been measured in thin foils of C, Ni, Au, Al2O3 and Mylar as a function of fragment mass and energy. The chosen stopping materials are frequently used as the backing of sources and targets or entrance windows of gas detectors. The experimental setup allowed registration of velocities of two fission fragments and energy of one of them. In this way fragment masses could be unambiguously determined and the pulse-height defect of the silicon detector verified. The measured stopping power data for fission fragments cover masses between A = 101 and A = 148. The results are compared with semi-empirical predictions of SRIM 2003 code, LSS theory and theoretical calculation by Sigmund (PASS code). The best representations of the data are achieved by a semi-empirical formula based on classical Bohr theory. The formula was successfully tested also on the available data for Ar, Ca, Kr, Xe and Au ions in the energy range 0.2–6 MeV/u slowing down in carbon, nickel and gold.