Fission-fragment detector for DANCE based on thin scintillating films

Abstract

A fission-fragment detector based on thin scintillating films has been built to serve as a trigger/veto detector in neutron-induced fission measurements at DANCE. The fissile material is surrounded by scintillating films providing 4π detection of the fission fragments. The scintillation photons were registered with silicon photomultipliers. A measurement of the 235 U(n, f) reaction with this detector at DANCE revealed a correct time-of-flight spectrum and provided an estimate for the efficiency of the prototype detector of 11.6(7)%. Design and test measurements with the detector are described.

Development of a liquid scintillator based active fission target for FIPPS

“…One limiting aspect of such studies, especially when investigating isotopes with small fission yields, is the γ-ray background originating from β decays of radioactive fission products, particularly compromising the quality of the coincidence energy spectra. In the past fission tagging devices have been developed for measurements of fission and neutron capture cross sections of actinides [9][10][11], fission γ-ray calorimetry [12,13] and measurements of fission neutron distributions [14,15]. The direct detection of one or both fission fragments has been achieved e.g.…”

“…The direct detection of one or both fission fragments has been achieved e.g. with fission ionization chambers [9,14], parallel plate avalanche counters [10,12], Micromegas [11], scintillating gases [15] or thin scintillating films [13]. Although the fission tagging detectors have been versatile for fission studies, they are not suitable for γ-ray spectroscopy due to the long flight-path of the fission fragments, causing Doppler shifts of the emitted γ rays.…”