Exploring the spin states of Zr-90 populated by (p, p'), (p, d), and (p, t) reactions

The Zr-90 nucleus was produced by three different reactions: Zr-90(p,p'), Zr-91(p,d), and Zr-92(p,t), and the spin-parity (J(pi)) population of the Zr-90 states produced by these reactions was studied to investigate the surrogate reaction approach, which aims at indirectly determining cross sections for compound-nuclear reactions involving unstable targets such as Zr-89(n,gamma). Discrete gamma-rays, associated with the de-excitation of Zr-90 and Zr-89, were measured in coincidence with light ions at Zr-90 excitation energies extending above the neutron separation energy. Low-lying states populated by (p,d) and (p,t) reactions agreed well with the previous measurements. The measured. transition systematics were used to gain insights into the J(pi) distribution of Zr-90 around the neutron separation energy and it was found that the (p,p') reaction preferentially produces lower J states than (p,d) and (p,t) reactions in the studied energy region.