Experimental studies and cascade-exciton model analysis of negative pion induced fission in gold and bismuth

Fission induced by energetic negative pions in gold and bismuth has been studied experimentally and theoretically. CR-39 dielectric track detectors in 4π-geometry were used to determine experimental cross sections, and the computer code CEM95 has been used for theoretical calculations. Experimental fission cross sections for gold have been determined at energies of 500, 672, 1068 and 1665 MeV, and for bismuth at energies of 500, 672 and 1068 MeV. The targets and detectors were irradiated at the AGS of Brookhaven National Laboratory (USA). Theoretical fission cross sections were calculated from 50 MeV to 2500 MeV to compare with a wider range of measurements. Good agreement is observed among the measured and computed results. For validation of the code CEM95 and our methodology, we also benchmarked fission cross sections induced by protons and neutrons on targets of lead and bismuth, and for pions on gold and bismuth over a wide energy range.