Analysis of the FIC detector data at the n_TOF facility

Fission cross-section measurements with the Fast Ionization Chamber (FIC) at the CERN n_TOF facility were challenged by intense signals due to γ-rays and ultra-relativistic particles from the impact of the 20 GeV proton pulses on the neutron spallation target. A method for analyzing the data taken with Flash Analog to Digital Converters (FADC) was developed to treat these problems in an automated way to provide a reliable background subtraction and a fit routine for identifying fission events even at high energies. The analysis is illustrated at the example of the fission cross-section of 238U relative to that of 235U in the energy range from 40 keV to 300 MeV.