Muon capture and fission phenomena in actinide muonic atoms
The interactions of stopped muons with /sup 232/Th, /sup 235/ /sup 238/U, /sup 237/Np, and /sup 239/ /sup 242/Pu nuclei were studied with the muon beam of the Los Alamos Meson Physics Facility. Time distributions were obtained of electrons produced by bound-muon decay and of neutrons and fission fragments resulting from nuclear ..mu.. capture. In addition, time distributions of neutrons attributed to ..mu.. capture by fission fragments were obtained; these neutrons were identifed by the prior observation of a fission caused by a radiationless transition in the muon cascade, resulting in ..mu.. capture by one of the fission fragments thus produced. The experimental results are applied to questions concerning the phenomenology of ..mu.. capture in heavy elements. The previously observed apparent dependence of observed capture rate on experimental method is shown to be caused by misidentification of events resulting from the disappearance of muons bound to fission fragments, rather than by population of shape-isomeric states in the excited nucleus following a radiationless transition. The true capture rates characteristic of the nuclei studied are compared with theoretical predictions. Capture rates for muons bound to fission fragments are inferred and found to be consistent with capture rates expected to be exhibited by muons bound to heavy fragments produced in the asymmetric mass division, rather than to light fragments. This finding is shown to be consistent with an adiabatic treatment of the muon motion at the time of fission. Alterations in the GAMMA/sub n/GAMMA/sub f/ ratios for nuclei to which muons are bound are taken as evidence for a change in the height of the fission barrier owing to a lessening of the Coulomb repulsion in the presence of the muon.
- Research Organization:
- Rochester Univ., NY (USA)
- OSTI ID:
- 5446676
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
74 ATOMIC AND MOLECULAR PHYSICS
FISSION FRAGMENTS
MUON REACTIONS
CAPTURE
FISSION
MUONIC ATOMS
BETA DECAY
NEPTUNIUM
NEPTUNIUM 237 TARGET
PLUTONIUM
PLUTONIUM 239 TARGET
PLUTONIUM 242 TARGET
THORIUM
THORIUM 232 TARGET
URANIUM
URANIUM 235 TARGET
URANIUM 238 TARGET
ELECTRONS
EXPERIMENTAL DATA
FISSION BARRIER
ISOLATED VALUES
NEPTUNIUM 237
NEUTRONS
NUCLEAR REACTION KINETICS
PLUTONIUM 239
PLUTONIUM 242
RADIATIONLESS DECAY
THORIUM 232
URANIUM 235
URANIUM 238
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ACTINIDES
ALPHA DECAY RADIOISOTOPES
ATOMS
BARYONS
CHARGED-PARTICLE REACTIONS
DATA
DATA FORMS
DE-EXCITATION
DECAY
ELEMENTARY PARTICLES
ELEMENTS
ENERGY TRANSFER
ENERGY-LEVEL TRANSITIONS
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FERMIONS
HADRONS
HEAVY NUCLEI
INFORMATION
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
KINETICS
LEPTON REACTIONS
LEPTONS
METALS
MINUTES LIVING RADIOISOTOPES
NEPTUNIUM ISOTOPES
NUCLEAR FRAGMENTS
NUCLEAR POTENTIAL
NUCLEAR REACTIONS
NUCLEI
NUCLEONS
NUMERICAL DATA
ODD-EVEN NUCLEI
PLUTONIUM ISOTOPES
POTENTIALS
RADIOISOTOPES
REACTION KINETICS
TARGETS
THORIUM ISOTOPES
TRANSURANIUM ELEMENTS
URANIUM ISOTOPES
YEARS LIVING RADIOISOTOPES
652025* - Nuclear Properties & Reactions
A=220 & above
Experimental- Nuclear Reactions & Scattering- (-1987)
652026 - Nuclear Properties & Reactions
A=220 & above
Experimental- Spontaneous & Induced Fission- (-1987)
640303 - Atomic
Molecular & Chemical Physics- Positronium
Muonium
& Muonic & Mesic Atoms & Molecules