Speaker
Description
Understanding the origin of elements in our universe is an inevitable mission for modern nuclear physics. It is known that neutron-deficient stable isotopes, referred to as $p-$nuclei, are synthesized through the $p$-process (or $\gamma$-process) triggered by photo-disintegration in supernovae. One of the major issues that remain unresolved is the anomalously large abundances for certain lighter $p-$nuclei in the current astrophysical scenario, such as $^{92,94}$Mo and $^{96,98}$Ru. A new scenario to account for the production of lighter $p-$nuclei is the neutrino driven rapid-proton capture ($\nu p$) process, which is predicted to occur in the core collapse supernovae. While the $\nu p-$process has been well-understood theoretically for the past decade, large uncertainties remain due to the lack of experimental data, especially for the neutron capture rate of the most critical waiting point in the $\nu p-$process: $^{56}$Ni, which has a long $\beta$ decay lifetime of 6 days and thus dominates the abundance of heavier $p-$nuclei. Since direct determination of the reaction cross section of $^{56}$Ni($n,p$)$^{56}$Co is rather challenging, we have applied the surrogate method instead by measuring the ($d,p$) reaction.
The experiment was performed at OEDO-SHARAQ beamline at RIBF, RIKEN. The secondary $^{56}$Ni beam was produced by the projectile fragementation of $^{78}$Kr beam, purified by BigRIPS separator and energy-degraded by OEDO. Recoiled protons were measured to establish the missing mass spectroscopy. Decay channels were identified by measuring projectile-like nuclei transporting through the high-resolution spectrometer SHARAQ. In this presentation, details of the experimental setup and preliminary results will be presented.
