ISOLDE Seminar

Study of 35,36,37Ca by means of (p,d) and (p,t) transfer reactions

by Louis Lalanne (IJCLab)




During summer 2018, an experiment to study 35,36,37Ca has been performed at GANIL. The physical motivations of such a measurement are both linked to nuclear structure, with the study of isospin symmetry breaking and shell gap evolution at the proton drip-line, and to nuclear astrophysics.

Those nuclei were studied by means of (p,d) and (p,t) transfer reactions. Radioactive beams of 37Ca and 38Ca, produced with the LISE spectrometer, were tracked by two sets of position-sensitive detectors before being sent on a liquid hydrogen cryogenic target of liquid H, in which (p,d) and (p,t) transfer reactions took place. 8 MUST2 Silicon telescopes were used to identify and measure the energy and angle of light particles emitted at forward angles. A assembly of three detectors (ionization chamber, drift chamber and plastic scintillator) was used to detect the transfer-like nuclei. During the analysis, excited states were selected by identifying a deuteron or triton particle in MUST2, in coincidence with outgoing Ca or K nuclei, corresponding to states that underwent gamma or one-proton decay, respectively.

The mass of 35Ca and 34K have been measured for the first time. The full spectroscopy of 36Ca and 37Ca has been obtained and new excited states have been identified in both nuclei. Isospin symmetry breaking is observed in the new discovered states of 36Ca. Furthermore the new observed states in 37Ca were used to study the effect of the tensor force on the neutron d3/2−d5/2 spin-orbit splitting. With the experimental results and the help of shell-model calculations, the 35K(p,γ))36Ca reaction rate has been strongly constrained, helping a better understanding of the rpprocess in X-ray burst. Those results will be presented together with the experimental setup and the analysis.