Eur. Phys. J. A (2018) 54: 7
https://doi.org/10.1140/epja/i2018-12429-2

Regular Article - Experimental Physics

Measurement of the ²³⁴U(n, f ) cross-section with quasi-monoenergetic beams in the keV and MeV range using a Micromegas detector assembly

¹ National Technical University of Athens, Department of Physics, Zografou Campus, Athens, Greece
² European Organisation for Nuclear Research (CERN), Geneva, Switzerland
³ Tandem Accelerator Laboratory, Institute of Nuclear and Particle Physics, N.C.S.R. Demokritos, Aghia Paraskevi, Athens, Greece

^* e-mail: athanasios.stamatopoulos@cern.ch

Received: 15 September 2017
Accepted: 13 November 2017
Published online: 23 January 2018

Abstract

The ²³⁴U neutron-induced fission cross-section has been measured at incident neutron energies of 452, 550, 651 keV and 7.5, 8.7, 10 MeV using the ⁷Li (p, n) and the ²H(d, n) reactions, respectively, relative to the ²³⁵U(n, f ) and ²³⁸U(n, f ) reference reactions. The measurement was performed at the neutron beam facility of the National Center for Scientific Research “Demokritos”, using a set-up based on Micromegas detectors. The active mass of the actinide samples and the corresponding impurities were determined via -spectroscopy using a surface barrier silicon detector. The neutron spectra intercepted by the actinide samples have been thoroughly studied by coupling the NeuSDesc and MCNP5 codes, taking into account the energy and angular straggling of the primary ion beams in the neutron source targets in addition to contributions from competing reactions (e.g. deuteron break-up) and neutron scattering in the surrounding materials. Auxiliary Monte Carlo simulations were performed making combined use of the FLUKA and GEF codes, focusing particularly on the determination of the fission fragment detection efficiency. The developed methodology and the final results are presented.