Changes in target fragmentation mechanisms with increasing projectile energy in intermediate energy nuclear collisions

Journal Article · Wed Feb 28 19:00:00 EST 1990 · Physical Review, C (Nuclear Physics); (USA)

DOI:https://doi.org/10.1103/PhysRevC.41.973· OSTI ID:6915401

Loveland, W ^[1]; Aleklett, K; Sihver, L ^[2]; Xu, Z; Casey, C ^[1]; Morrissey, D J ^[3]; Liljenzin, J O ^[4]; de Saint-Simon, M ^[5]; Seaborg, G T ^[6]

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1. Chemistry Department, Oregon State University, Corvallis, Oregon 97331 (USA)
2. Studsvik Neutron Research Laboratory, S-61182, Nykoeping, Sweden (SE)
3. National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (USA)
4. Department of Chemistry, University of Oslo, Oslo, Norway (NO)
5. Laboratoire Rene Bernas, F-91406 Orsay, France (FR)
6. Lawrence Berkeley Laboratory, Berkeley, California 94720 (USA)

We have measured the target fragment production cross sections and angular distributions for the interaction of 16 MeV/nucleon {sup 32}S, 32 MeV/nucleon {sup 40}Ar, and 44 MeV/nucleon {sup 40}Ar with {sup 197}Au. We have deduced the fragment isobaric yield distributions and moving frame angular distributions from these data. The fission cross sections decrease with increasing projectile energy and the heavy residue cross sections (which are much larger than previous counter measurements) increase. There is an unusual change in the fragment isobaric yield distributions in the reactions induced by 32 MeV/nucleon {sup 40}Ar and 44 MeV/nucleon {sup 40}Ar. We have used the symmetry properties of the moving frame distributions to show the relative time scale of the reaction mechanisms involved. The fission fragments associated with the peripheral collision peak in the folding angle distribution originate in a normal, slow fission process in which statistical equilibrium has been established. At the two lowest projectile energies, the fission fragments associated with the central collision peak in the folding angle distribution originate in part in fast, nonequilibrium processes. At the highest projectile energies, there are no fission fragments associated with high-momentum-transfer events. The intermediate mass fragments originate primarily in events in which statistical equilibrium has not been established.

• DOE Contract Number: AM06-70RL02227
• OSTI ID: 6915401
• Journal Information: Physical Review, C (Nuclear Physics); (USA), Journal Name: Physical Review, C (Nuclear Physics); (USA) Vol. 41:3; ISSN 0556-2813; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

651920* -- Nuclear Properties & Reactions
A=190-219
Experimental
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR DISTRIBUTION
ARGON 40 REACTIONS
CHARGED-PARTICLE REACTIONS
CROSS SECTIONS
DATA
DISTRIBUTION
ENERGY DEPENDENCE
ENERGY RANGE
EXPERIMENTAL DATA
FISSION
FISSION YIELD
GEV RANGE
GEV RANGE 01-10
GOLD 197 TARGET
HEAVY ION REACTIONS
INFORMATION
MEV RANGE
MEV RANGE 100-1000
NUCLEAR FRAGMENTATION
NUCLEAR REACTION YIELD
NUCLEAR REACTIONS
NUMERICAL DATA
SULFUR 32 REACTIONS
TARGETS
YIELDS