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

The 90 Zr nucleus was produced by three different reactions: 90 Zr( p , p ’), 91 Zr( p , d ), and 92 Zr( p , t ), and the spin-parity ( J π ) population of the 90 Zr 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 89 Zr( n , γ ). Discrete γ-rays, associated with the de-excitation of 90 Zr and 89 Zr, were measured in coincidence with light ions at 90 Zr 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 γ transition systematics were used to gain insights into the J π distribution of 90 Zr 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.