Cross sections of the O-16(n,alpha gamma) reaction at 14.7 MeV. Final report for the period 15 December 1992 - 14 December 1993

摘要

The discrete cross section of gamma ray production cross sections in the O-16(n,alpha gamma)C-13 reaction was measured at 14.7 MeV. The experiment was based on the time-correlated associated particle method and the setup was designed in a way to utilize fully the advantage of strong spatial and time correlations between neutrons and alpha particles for background reduction. Neutrons were produced in the TiT target by the T(D,n) alpha reaction. Associated alpha particles were detected by a fast plastic scintillation counter placed at an angle of 135 deg. C with respect to the D(sup +) beam. Photons emitted from the sample were registered by a HPGe detector. Cross sections were determined relatively to the well known reference Cr-52(n,n' gamma) reaction with precision better than 10%. It was found that Doppler effects play an important role in this very light system. For the short-lived 3/2 level, authors accounted for this fact and arrived at the cross section that is comparable roughly to the mean value of other known experimental data around 14 MeV. The total discrete gamma ray production to be (80.9 +- 5.4) mb was determined and the total O-16(n, alpha)C-13 cross section of (98.9 +- 6.4) mb was deduced. This later value is lower than the other experimental data as well as the ENDF/B-VI evaluation, however, it agrees with the JENDL-3 evaluation. 15 refs, 9 figs, 2 tabs. (Atomindex citation 28:026845)