Experimental studies at CERN-nTOF of the 230Th(n,f) reaction

Abstract: This work investigates the feasibility to perform an experiment at CERN n_TOF to study the fission cross section and fission fragment angular distribution (FFAD) of the 230Th(n,f) reaction. An analysis of fission fragment energy losses in the experimental target resulted in a choice of target thickness of 0.1 µm (100 µg/cm2 ), which yields good transmission out of the target at up to 45° emission angles from the target normal. A detection setup using ten PPAC detectors with nine thorium targets interleaved in between them was investigated, where the detectors and targets were tilted 45° with respect to the neutron beam. This makes it possible to measure all emission angles needed with respect to the neutron beam in order to determine the FFAD. For the experimental area EAR2 at n_TOF, a prediction of the count rate in the experiment resulted in low statistical uncertainties after a few weeks of beam time, which indicates that an experiment like this is feasible.