This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440

Anderson-Pugh, B.

Bacher, A.D.

Blatt, S.L.

Hausman, H.J.

Kovash, M.A.

Marchlenski, D.

McEllistrem, M.T.

Trice, J.

English

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ELASTI C SCATTERI NG AND CHARGE EXCHANGE REACTI ONS 
THE ISOVECTOR QUADRUPOLE RESONANCE IN 160 
M.A. Kovash, B. Anderson-Pugh, M.T. McEllistrem and J. Trice 
University of Kentucky, Lexington, Kentucky 40506 
S.L. Blatt, H.J. Hausman and D. Marchlenski 
Ohio State University, Columbus, Ohio 43210 
A.D. Bacher 
Indiana University Cyclotron Facility, Bloomington, Indiana 47405 
Cross sections and analyzing powers for radiative interest was increased by approximately 100% by 
proton capture into 160 have been measured to deduce resumming the measured energy distribution as observed 
the distribution of isovector electric quadrupole in the core and annular detectors. 
strength above the region of the giant dipole Gamma-ray angular distributions were recorded at 
resonance. While only about 20% of the energy-weighted 8 angles extending from 23O to 155O in the lab. 
E2 sum rule has been observed1 at lower energies, Interestingly, the measured analyzing powers at the 
microscopic calculations2 predict that the dominant limits of this angular range assumed their maximal 
resonant contribution should occur near 35 MeV, and values, where typically I A ~  1-0.64.7. These data 
extend to nearly 50 MeV of excitation. provide tight constraints on the parameters which 
Through simultaneous measurements of the angular describe the complexity of the angular distribution and 
distributions of both cross section and analyzing on the extent of El-E2 mixing which appears in 
power, the low partial-wave quadrupole strength can be interference terms. Our first analysis of these data 
accurately determined. We have measured these indicates that the El-E2 interference is strong. This 
distributions at proton beam energies of 20.3, 24.3 and will allow an accuate extraction of the magnitude and 
28.7 MeV, corresponding to excitation energies in 160 phase associated with the capture partial-waves and 
of approximately 31, 35 and 39 MeV. 3~~ for dipole radiation and the capture partial-wave 
Gamma-rays were detected in a NaI spectrometer 3 ~ 2  for electric quadrupole radiation. 
built at the University of Kentucky and consisting of a Replay and further analysis of these data are in 
core element 8" diameter x 10" deep, which is progress. 
surrounded by a NaI annulus of 1.75" thickness. 
1) S.S. Hanna et al., Phys. Rev. Lett. 32, 114 (1974). 
Background-free spectra were obtained by the combined 
2) K.F. Liu and N. Van Giai, Phys. Lett. s, 23 
use of TOF rejection of fast neutrons and cosmic-ray (1976). 
rejection with the active annular shield. The 3) M.A. Kovash, Proceedings of the LAMPF Workshop on 
Photon and Neutral Meson Physics, H. Crannel ed. 
detection efficiency for the -30 MeV gamma-rays of (1987). 


The Isovector Quadrupole Resonance in 16-O

https://scholarworks.iu.edu/dspace/bitstream/2022/901/1/iucf_1986_22.pdf

The Isovector Quadrupole Resonance in 16-O

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