Department of Physics, Panjab University, Chandigarh, India

Department seminar

Date and time: 24 August 2015 (Monday), 3:00 pm
Venue: Seminar Hall

Title: Development of technique and measurement of fusion excitation function using radioactive ion beam

Speaker: Dr. Varinderjit Singh, Nuclear Chemistry Group, Indiana University, Bloomington, Indiana, USA

Abstract: Fusion of neutron-rich light nuclei in the outer crust of an accreting neutron star has been proposed as responsible for triggering X-ray super-bursts. The underlying hypothesis in this proposition is that the fusion of neutron-rich nuclei is enhanced as compared to stable nuclei. To investigate this hypothesis, our group has developed a technique to measure fusion excitation function of light nuclei with low beam intensity and performed a series of experiments at Florida State University. During these experiments we measured the fusion excitation function for 18O and 19O nuclei incident on a 12C target. Fusion cross-section measurement up to sub μb level has been performed for 18O beam. In our recent measurement, a beam of 19O was produced by the 18O(d,p) reaction and separated using the RESOLUT mass spectrometer. The resulting 19O beam bombarded a 100 μg/cm2 12C target at an intensity of 2–4 × 103 p/s. Evaporation residues resulting from the de-excitation of the fusion product were distinguished by measuring their energy and time-of-flight. Using silicon detectors, microchannel plate detectors, and an ionization chamber, evaporation residues were detected in the angular range θlab ≤ 23° with high efficiency. We are aiming to measurethe fusion cross-section to approximately the 100 mb level. The measured excitation function will be compared to theoretical predictions.