The FIGARO Facility at Los Alamos: Capabilities and First Results

Abstract

A new beam line at the fast neutron spallation source at Los Alamos Neutron Science Center has been constructed for studies of neutron-induced reactions producing gamma rays, internal conversion electrons or neutrons. This facility, called FIGARO (Fast neutron-induced GAmma-Ray Observer), follows on the great successes of GEANIE (described in other contributions to this conference), by detecting de-excitation gamma rays with high-resolution germanium detectors. FIGARO has fewer gamma-ray detectors than GEANIE, but instead offers other features including: extremely good collimation of the neutron beam for background reduction, a flexible experimental area to optimize detection efficiency and to allow evaluation of other detectors such as ICEBALL-II for internal conversion electrons, inclusion of neutron detectors for the study of neutron-gamma coincidences, beam time to relieve the scheduling pressure on GEANIE, and a PC-based data acquisition system. Our initial measurements include level density studies through 59Co(n, xgamma) reactions to complement our previous 59Co(n, xalpha) measurements, reaction studies of MeV neutrons on 99Tc with the goal of determining cross sections relevant to transmutation and neutron transport in the design of facilities to incinerate nuclear waste, and an assessment of measuring internal conversion electrons, rather than gamma rays, produced by neutron excitation of actinides.