Spin differences in the Zr90 compound nucleus induced by (p,p') , (p,d) , and (p,t) surrogate reactions

• Published in: Physical review. C, Nuclear physics Nuclear physics, 2015-11, Vol.92 (5)
• Main Authors: Ota, S., Burke, J. T., Casperson, R. J., Escher, J. E., Hughes, R. O., Ressler, J. J., Scielzo, N. D., Thompson, I. J., Austin, R. A. E., Abromeit, B., Foley, N. J., McCleskey, E., McCleskey, M., Park, H. I., Saastamoinen, A., Ross, T. J.
• Format: Article
• Language: English
• Subjects: NUCLEAR PHYSICS AND RADIATION PHYSICS
• ISSN: 0556-2813; 1089-490X

Here, the effect of the production mechanism on the decay of a compound nucleus is investigated. The nucleus 90Zr was produced by three different reactions, namely 90Zr (p,p') 90Zr, 91Zr (p,d) 90Zr, and 92Zr (p,t) 90Zr , which served as surrogate reactions for 89Zr (n,γ). The spin-parity (Jπ) distributions of the states populated by these reactions were studied to investigate the surrogate reaction approach, which aims at indirectly determining cross sections for compound-nuclear reactions involving unstable targets such as 89Zr. Discrete γ rays, associated with transitions in 90Zr and 89Zr, were measured in coincidence with light ions for scattering angles of 25°–60° and 90Zr excitation energies extending above the neutron separation energy. The measured transition systematics were used to gain insights into the Jπ distributions of 90Zr. The 90Zr (p,p') reaction was found to produce fewer γ rays associated with transitions involving high spin states (J = 6–8 ℏ) than the other two reactions, suggesting that inelastic scattering preferentially populates states in 90Zr that have lower spins than those populated in the transfer reactions investigated. The γ-ray production was also observed to vary by factors of 2–3 with the angle at which the outgoing particle was detected. These findings are relevant to the application of the surrogate reaction approach.