Neutron-induced cross sections of short-lived nuclei via the surrogate reaction method

G Boutoux,X Derkx,P Romain,F Gunsing,I Companis,O Roig,V Méot,L Gaudefroy,B Jurado,G Barreau,T Faul,N Pillet,L Tassan‐Got ,M Aïche,O Sérot,E Bauge,J Taïeb ,Camille Theroine ,S Czájkowski ,J M Daugas ,J.T Burke,Pierre Morel ,L Mathieu,I Matéa ,N Capellán

doi:10.1051/epjconf/20122101002

Abstract

The measurement of neutron-induced cross sections of short-lived nuclei is extremely difficult due to the radioactivity of the samples. The surrogate reaction method is an indirect way of determining cross sections for nuclear reactions that proceed through a compound nucleus. This method presents the advantage that the target material can be stable or less radioactive than the material required for a neutron-induced measurement. We have successfully used the surrogate reaction method to extract neutron-induced fission cross sections of various short-lived actinides. In this work, we investigate whether this technique can be used to determine neutron-induced capture cross sections in the rare-earth region.

Highlights

Neutron-induced radiative-capture cross sections of short-lived nuclei are crucial for fundamental nuclear physics and for applications such as reactor physics and astrophysics
Applying a threshold to the gammaenergy in order to suppress the contribution of the (3He, pnγ)175Lu* channel, this ratio remains essentially constant from E*=5.5 MeV to Sn, see figure 3
The big discrepancies found at low E* can be explained by the differences between the spin distributions populated in transfer and neutron-induced reactions

Summary

Introduction

Neutron-induced radiative-capture cross sections of short-lived nuclei are crucial for fundamental nuclear physics and for applications such as reactor physics and astrophysics. These data are needed to test s- and r-process models. The surrogate reaction method is an indirect way of determining cross sections for compound nuclear reactions. The left part of figure 1 illustrates a neutron-induced reaction on target A-1, which leads to the compound-nucleus A at an excitation energy E*. On the right part of figure 1, in the surrogate reaction method, the same compound nucleus A* is produced by a transfer reaction between a projectile y (a light charged particle) and a target X.

Objectives

Results

Conclusion