Measurement of the inelastic neutron scattering cross section of ⁵⁶Fe

¹ Forschungszentrum Dresden-Rossendorf, Postfach 51 01 19, 01314 Dresden, Germany
² Technische Universität Dresden, Institut für Kern- und Teilchenphysik, 01062 Dresden, Germany
³ Physikalisch-Technische Bundesanstalt, 38116 Braunschweig, Germany

^a e-mail: a.junghans@fzd.de

Abstract

At the superconducting electron linear accelerator ELBE at Forschungszentrum Dresden-Rossendorf the neutron time-of-flight facility nELBE has become operational. Fast neutrons in the energy range from 200 keV to 10 MeV are produced by the pulsed electron beam from ELBE impinging on a liquid lead circuit as a radiator. The short beam pulses of 10 ps provide the basis for an excellent time resolution for neutron time-of-flight experiments, giving an energy resolution of about <1% at 1 MeV with a short flight path of 5 m. By means of a “double-time-of-flight” setup the (n,nâγ) cross section to the first excited state of ⁵⁶Fe has been measured over the whole energy range without knowledge about cross sections of higher-lying levels. Plastic scintillators were used to detect the inelastically scattered neutron and BaF₂ detectors to detect the correlated γ-ray.