Abstract
M.Sc. (Physics)
At some locations along the s-process reaction path, there exists nuclei with _-decay rates that competes with the neutron capture rates. Leading to a new possibility in s-process path because the radioactive nucleus may capture a neutron instead of undergoing the expected _ decay. As a result the sprocess is split into two to account for neutron capture possibility. The nuclei at which this occur are are known as s-process branch-point nuclei, which are worth looking into because they can be used to estimate stellar temperature and neutron density at the s-process site. However studying has proven to be a challenge since their (n; ) cross section are usually not measurable by direct measurements. One of these branch-point nuclei is 185W, and is important due to the Re-Os cosmochronology whereby the 187Re _187Os pair may be used as a chronometer to estimate stellar nucleosynthesis duration in the universe before the formation our solar system. However, the existence of branch point nuclei at leads to inconclusive analysis. Hence the need for better constraints of their (n; ) cross-sections. In this work the nuclear level density and strength function of 186;187W were measured with th Oslo method using 186W(d; d0) and 186W(d; d0) reactions. These new experimental data were successfully used to constrain 185W(n; ) cross sections within the Hauser-Feshbach model.