Reactions of /sup 40/Ar with /sup 160/Dy, /sup 164/Dy, and /sup 174/Yb

Journal Article · Wed Sep 01 04:00:00 EDT 1976 · Phys. Rev., C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.14.1038· OSTI ID:7356121

LeBeyec, Y; Hahn, R L; Toth, K S; Eppley, R

Excitation functions for nuclear reactions induced by /sup 40/Ar ions were measured for the reactions /sup 164/Dy(/sup 40/Ar, xn)/sub x/Po and for the reactions /sup 160/Dy(/sup 40/Ar, xn), /sup 174/Yb(/sup 40/Ar, xn), and /sup 174/Yb(/sup 40/Ar, pxn). For all of the systems studied, the (Ar, xn) reactions only make up a small part of the total reaction cross section of approx. 2 b; the largest cross sections encountered in each system were (at the peaks of the respective excitation functions) 30 mb for /sup 164/Dy(Ar, 5n), 10 mb for /sup 160/Dy(Ar, 4n), and 5 mb for /sup 174/Yb(Ar, 4n--5n). The probabilities P/sub xn/ of neutron emission in the compound systems /sup 204/Po and /sup 200/Po were found to be very different, with respective maximum probabilities for the emission of four, five, and six neutrons of 0.064, 0.035, and 0.016 for /sup 204/Po, and 0.010, 0.0025, and 0.0003 for /sup 200/Po. Calculations performed with a statistical-model code, which includes angular-momentum effects and fission competition, are able to reproduce the shapes and magnitudes of the experimental excitation functions, although there is a systematic energy difference, approx. 10 MeV, between theory and the data. These model-dependent analyses describe in detail how the particle evaporation and fission deexcitation modes vary with angular momentum and excitation energy. The observed large differences in P/sub xn/ values for /sup 204/Po and /sup 200/Po are seen to arise from small difference, approx. 1.2 MeV, between the values of S/sub n/ - B/sub f/, the difference of neutron-separation and fission-barrier energies, in each compound system. (AIP)

• Research Organization: Institut de Physique Nucleaire, Orsay, France
• OSTI ID: 7356121
• Journal Information: Phys. Rev., C; (United States), Journal Name: Phys. Rev., C; (United States) Vol. 14:3; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

651825* -- Nuclear Properties & Reactions
A=150-189
Experimental-- Nuclear Reactions & Scattering-- (-1987)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALKALI METAL ISOTOPES
ALKALINE EARTH ISOTOPES
ANGULAR MOMENTUM
ARGON 40 REACTIONS
BARYONS
CHARGED-PARTICLE REACTIONS
COMPOUND-NUCLEUS REACTIONS
CROSS SECTIONS
DYSPROSIUM 160 TARGET
DYSPROSIUM 164 TARGET
ELEMENTARY PARTICLES
ENERGY RANGE
EXCITATION FUNCTIONS
FERMIONS
FRANCIUM ISOTOPES
HADRONS
HEAVY ION REACTIONS
ISOTOPES
MATHEMATICAL MODELS
MEV RANGE
MEV RANGE 100-1000
NEUTRONS
NUCLEAR REACTIONS
NUCLEONS
POLONIUM ISOTOPES
RADIUM ISOTOPES
STATISTICAL MODELS
TARGETS
YTTERBIUM 174 TARGET