Research Projects

Neutron-induced radiative-capture cross sections along the s-process path are crucial for understanding elemental abundances and probing stellar evolution through contemporary astrophysical models. While most s-process abundances are now well understood, a few unresolved issues remain, primarily concerning the branchings - around 20 isotopes along the s-process path have comparable neutron-capture and beta-decay rates, creating waiting points. Investigating these branchings is critical, as the resulting abundance pattern provides insights into temperature and neutron density at the s-process site. One such important branching in encountered at the 79Se nucleus. However, experimental estimates of the neutron-capture cross section of 79Se are limited owing to its unstable nature. Transfer reactions can be an alternate rote to probe this cross section. Since the 79Se(n,gamma) cross section depends on the gamma-decay widths of the neutron-unbound levels in 80Se, measurement of only the ejectile in a transfer reaction would not suffice in this reaction. This project proposes to undertake such measurement employing the particle-gamma coincidence technique. The measurement would employ 6Li beam at the FRENA facility, expected to be available soon, to populate the desired 80Se compound nucleus in the 76Ge(6Li,d) reaction. To facilitate the aforementioned measurement, this proposal seeks funding for the purchase of a pair of Si strip detectors, alongside a Digital Data Acquisition (DDAQ) system. This proposed DDAQ system would be specifically configured for particle-particle and particle-gamma coincidence measurements with heavy-ion beams. The existing gamma-detectors at SINP would be put to use for implementation of the coincidence system. In the later stages, the system would be configured for particle-neutron coincidences, that would permit studies on a multitude of (p,n), (alpha,n) as well as (gamma,n) reactions. A new robust DDAQ system based on CAEN digitizers will be developed to couple the particle and gamma-detectors, first using standardized alpha and gamma radioactive sources. Digitizers with sampling rates ~100-125 MHz would be ideal choice for both Si and HPGe semiconductor detectors, while those with rates of 250-500 MHz would be optimal for the scintillator detectors. Once successfully characterised and optimised for the coincident measurement, the DDAQ system will be used to support in-beam experiments at FRENA. The effective integration of telescopes made out of Si strip detectors with HPGe detectors into a coherent setup that can synchronize data from multiple channels will improve the ability to capture complex events in real-time. All data would be recorded on local storage and cloud-based solutions would be explored in the future. This project will serve as a key resource for advancing research in nuclear astrophysics in the country while providing critical infrastructure for future projects.