First results from the new double velocity-double energy spectrometer VERDI
Today fission research focusses on obtaining precise information on the amount of isotopes produced in nuclear fission and the production methods involved. Those data were again of high priority in the context of high burn-up scenarios and nuclear waste minimisation. Also, the number of neutrons emitted from fission fragments received particular interest for fast-spectrum reactors of the 4th Generation. The simultaneous measurement of both fragments' velocity and kinetic energy with sufficient accuracy allows for determining the fragmented mass before (A*) and after (A) emission of prompt neutrons. The difference between A* and A is equal to the number of prompt neutrons.
The team from the JRC-Institute for Reference Materials and Measurements (IRMM) developed such a fission-fragment spectrometer, and its commissioning involved measuring the mass yield and average prompt neutron data as a function of fragment mass from the spontaneous fission of 252Cf. The double velocity - double energy spectrometer VERDI, which stands for VElocity foR direct particle Identification, has the characteristics of responding to questions formulated by the nuclear fission community.
The successful implementation of VERDI has already resulted in a request by the French CEA Saclay for collaboration aimed at carrying out common experiments at the Neutron For Science (NFS) facility at GANIL.