Future research program on prompt -ray emission in nuclear fission

S. Oberstedt; R. Billnert; F. -J. Hambsch; M. Lebois; A. Oberstedt; J. N. Wilson

doi:10.1140/epja/i2015-15178-8

2023 Impact factor 2.6

Hadrons and Nuclei

Perspectives on Nuclear Data for the Next Decade

Open Access

Eur. Phys. J. A (2015) 51: 178
https://doi.org/10.1140/epja/i2015-15178-8

Review

Future research program on prompt $\gamma$ -ray emission in nuclear fission

S. Oberstedt¹^*, R. Billnert¹^,2, F. -J. Hambsch¹, M. Lebois³, A. Oberstedt²^,4 and J. N. Wilson³

¹ European Commission, Joint Research Centre IRMM, 2440, Geel, Belgium
² Fundamental Fysik, Chalmers Tekniska Högskola, 41296, Göteborg, Sweden
³ Institut de Physique Nucleaire Orsay, 91406, Orsay, France
⁴ Ossolution Consulting, 70353, Örebro, Sweden

^* e-mail: Stephan.OBERSTEDT@ec.europa.eu

Received: 5 May 2015
Accepted: 15 July 2015
Published online: 23 December 2015

Abstract

In recent years the measurement of prompt fission $\gamma$ -ray spectra (PFGS) has gained renewed interest, after about forty years since the first comprehensive studies of the reactions ²³⁵U(n_th, f), ²³⁹Pu(n_th,f) and ²⁵²Cf(sf). The renaissance was initiated by requests for new values especially for $\gamma$ -ray multiplicity and average total energy release per fission in neutron-induced fission of ²³⁵U and ²³⁹Pu. Both isotopes are considered the most important ones with respect to the modeling of innovative cores required for the Generation-IV reactors, the majority working with fast neutrons. During the last 5 years we have conducted a systematic study of spectral data for thermal-neutron-induced fission on ²³⁵U and ²⁴¹Pu as well as for the spontaneous fission of ²⁵²Cf with unprecedented accuracy. From the new data we conclude that those reactions do not considerably contribute to the observed heat excess and suspect other reactions playing a significant role. Possible contributions may originate from fast-neutron-induced reactions on ²³⁸U, which is largely present in the fuel, or from $\gamma$ -induced fission from neutron capture in the construction material. A first experiment campaign on prompt $\gamma$ -ray emission from fast-neutron-induced fission on ^235,238U was successfully performed in order to test our assumptions. In the following we attempt to summarize, what has been done in the field to date, and to motivate future measurement campaigns exploiting dedicated neutron and photon beams as well as upcoming highly efficient detector assemblies.