Isobaric-spin violation in the reaction $sup 10$B(d,d')$sup 10$B

Journal Article · Tue Jan 01 04:00:00 EST 1974 · Phys. Rev., C, v. 9, no. 1, pp. 102-115

OSTI ID:4315042

Stocker, H; Browne, C P

The reaction /sup 10/B(d d')/sup 10/ investigated to determine the isobaric-spin violation in exciting the lowest T=l state of /sup 10/B at an excitation energy of 1.74 MeV. The extent and nature of the isobaric-spin- forbidden reaction was obtained by measuring yield curves at laboratory angles of 30, 45, and 77 deg using deuteron bombarding energies from 5 to 12 MeV and at 140 deg from 6.5 to 16 MeV. Simultaneously, data were obtained on the nearby isobaric-spin-allowed T=0 statc at 2.15 MeV. Generally, broad structure dominates the excitation functions at all angles but tends to disappear at higher bombarding energies. Angular distributions of deuterons leading both to the T = 0 and T=1 states were obtained at five bombarding energies between 6.5 and 12.0 MeV. The angular distributions both for the forbidden (T=1) and allowed (T=0) state are characterized by a trend to forward peaking with increasing bombarding energies although much less so for the T=l state. The total cross sections were measured, and the ratios of the forbidden yield to allowed yield were found to decrease linearly from 0.69% at 6.5 MeV to 0.16% at 12 MeV. In an attempt to describe the angular distributions in terms of a direct-reaction mechanism, distorted-wave Born-approximation (DWBA) calculations were performed assuming collective excitations for the residual nucleus. calculations. Indications are that the reaction /sup 10/B(d,d')/sup 10/B proceed s through states very high in the compound nucleus /sup 11/C, where the isobaric-spin violation originates in Coulomb mixing of T=1 and T=0 states of the same spin and parity. In view of the very small yield of deuterons leading to the lowest T=1 state in /sup 10/B, and in view of the background difficulties anticipated and experienced, a specialized charged-particle detection system was used, consisting of a position-sensitive gas proportional counter mounted on the focal surface of a broad-range magnetic spectrograph. This constitutes the first observation of the lowest T=1 state in / sup 10/B by the present reaction. (auth)

• Research Organization: Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556
• NSA Number: NSA-29-022870
• OSTI ID: 4315042
• Journal Information: Phys. Rev., C, v. 9, no. 1, pp. 102-115, Journal Name: Phys. Rev., C, v. 9, no. 1, pp. 102-115; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

*BORON 10-- DEUTERON REACTIONS
ANGULAR DISTRIBUTION
ISOSPIN
MEV RANGE 01-10
MEV RANGE 10-100
N68351* --Physics (Nuclear
Experimental)--Nuclear Properties & Reactions
6 <= A <= 19--Nuclear Reactions & Scattering
TOTAL CROSS SECTIONS