Evaluation of cross sections for 14 important neutron-dosimetry reactions

The evaluation of the cross sections for the neutron dosimetry reactions 24Mg(n,p)24Na, 27Al(n,α)24Na, 58Ni(n,2n)57Ni, 64Zn(n,p)64Cu, 90Zr(n,2n)89Zr and 93Nb(n,n')93mNb carried out at the IRK about ten years ago were updated taking into account recent experimental results. Besides, new evaluations were performed for four additional dosimetry reactions, namely 52Cr(n,2n)51Cr, 59Co(n,2n)58Co, 93Nb(n,2n)92mNb and 197Au(n,2n)196Au. The deadlines for the retrieval of data for the different reactions lay between March 1989 and February 1990. The evaluations comprise the neutron energy range from threshold to 20 MeV, in a few cases this range is extended up to 21 MeV or 30 MeV. Cross sections and their uncertainties were evaluated in energy groups with widths of 0.1 MeV to 2.0 MeV, and relative correlation matrices of the evaluated cross sections at different energies were derived. The results of the evaluations are compared to the previous ones and to other recent evaluations reported in the literature. The main results of our previous evaluations for the reactiosn 19F(n,2n)18F, 31P(n,p)31Si, 63Cu(n,2n)62Cu and 103Rh(n,n')103mRh which remain unchanged are also given for completeness. The evaluations reported in this work will be included in the new version of the IRDF (International Reactor Dosimetry File) of the IAEA in ENDF/B-VI format. (orig.)