Measurement of the 6Li(n,α) neutron standard cross-section at the GELINA facility

The Li-6(n,alpha) reaction cross-section is commonly used as a reference cross section. However, it is only considered a neutron standard up to 1 MeV. For higher energies, there are discrepancies of several per cents between recent measurements and evaluated data files. In order to extend and establish Li-6 (n,alpha) as a neutron standard above 1 MeV these discrepancies must be resolved. Our measurement at the GELINA facility at JRC-IRMM in Geel, Belgium is ongoing. We are using a double twin Frisch-grid setup to detect both a-particles from two Li-6 targets and fission products from two U-235 reference targets. Our targets have thick backings but are employed in pairs, one forward facing and one backward facing. In this way we still cover, in principle, a solid angle of 4 pi. We present some preliminary results showing that the existing cross-section data is well reproduced around the resonance at 240 keV. The final data taking will start in the beginning of 2016, when the GELINA facility goes online again after a few months of shut down.