Production of neutron-rich Bi isotopes by transfer reactions

Journal Article · Thu May 31 20:00:00 EDT 1984 · Phys. Rev. C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.29.2160· OSTI ID:6792947

Eskola, K; Eskola, P; Fowler, M M; Ohm, H; Treher, E N; Wilhelmy, J B; Lee, D; Seaborg, G T

Production of neutron-rich Bi isotopes was investigated by irradiating Hg, Tl, and Pb targets with /sup 18/O ions in the 5--10 MeV/nucleon range. Following irradiation, bismuth was chemically separated and the yields of /sup 211 -213/Bi isotopes were determined via ..cap alpha..-emitting Po daughters. Effective residual transfers of /sup 3 -5/H to /sup 208/Pb, /sup 7,8/He to /sup 205/Tl, and /sup 8/Li to /sup 204/Hg were observed. Cross sections generally peaked in the 7--8 MeV/nucleon region and ranged from a high of approx.2 mb for /sup 3/He absorption to approx.0.6 nb for /sup 8/He absorption. Total ..cap alpha..- and ..beta..-decay branches of the J/sup ..pi../ = 9/sup -/, 25 min isomer of /sup 212/Bi were measured to be 67% and 33%, respectively, (3.2 +- 0.2)% of the decays being associated with ..beta..-delayed ..cap alpha..-particle emission. Production yields for the J/sup ..pi../ = 1/sup -/ ground state and 9/sup -/ and 15/sup -/ isomeric levels for /sup 212/Bi were extracted. The ratio of isomeric states to the ground state increased by more than two orders of magnitude over the energy range studied. However, the maximum value of the cross section ratio sigma(J/sup ..pi../ = 15/sup -/)/sigma(J/sup ..pi../ = 9/sup -/ ) was only 0.04, implying a low angular momentum transfer. The reactions were analyzed using the Wilczynski ''sum rule,'' which gave a rather poor fit to the results with respect to both the yield and the implied angular momentum transfer. The observed relatively high cross sections, modest angular momentum transfer, and broad excitation functions indicate that transfer processes provide a viable method for reaching neutron-rich nuclides in the heavy element region.

• Research Organization: Los Alamos National Laboratory, Los Alamos, New Mexico 87545
• OSTI ID: 6792947
• Journal Information: Phys. Rev. C; (United States), Journal Name: Phys. Rev. C; (United States) Vol. 29:6; ISSN PRVCA
• Country of Publication: United States
• Language: English

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALPHA DECAY
ALPHA DECAY RADIOISOTOPES
ANGULAR MOMENTUM
BETA DECAY
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY
BETA-MINUS DECAY RADIOISOTOPES
BISMUTH 212
BISMUTH ISOTOPES
BRANCHING RATIO
CHARGED-PARTICLE REACTIONS
DECAY
DIRECT REACTIONS
ENERGY LEVELS
ENERGY RANGE
HEAVY ION REACTIONS
HEAVY NUCLEI
HOURS LIVING RADIOISOTOPES
ISOTOPES
LEAD 208 TARGET
MERCURY 204 TARGET
MEV RANGE
MEV RANGE 10-100
MEV RANGE 100-1000
MOMENTUM TRANSFER
NUCLEAR REACTIONS
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
OXYGEN 18 REACTIONS
PARITY
PARTICLE PROPERTIES
RADIOISOTOPES
SPIN
STABLE ISOTOPES
TARGETS
THALLIUM 205
THALLIUM ISOTOPES
TRANSFER REACTIONS