Neutron yields and angular distributions produced in antiproton annihilation at rest in uranium

Journal Article · Fri May 01 04:00:00 EDT 1992 · Physical Review, C (Nuclear Physics); (United States)

DOI:https://doi.org/10.1103/PhysRevC.45.2332· OSTI ID:7301093

Chen, B; Armstrong, T A; Lewis, R A; Newton, R; Smith, G A ^[1]; Bocquet, J P; Malek, F ^[2]; Nifenecker, H ^[3]; Maurel, M; Monnand, E; Perrin, P; Ristori, C ^[4]; Ericsson, G; Johansson, T; Tibell, G ^[5]; Rey-Campagnolle, M ^[6]

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1. Laboratory for Elementary Particle Science, Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)
2. Institut des Sciences Nucleaires de Grenoble, 53 Avenue des Martyrs, 38026 Grenoble CEDEX (France)
3. Institut des Sciences Nucleaires de Grenoble CEDEX, 53 Avenue des Martyrs, 38026 Grenoble CEDEX (France) DRFMC/LIH Centre d'Etudes Nucleaires de Grenoble, Boite Postale 85X, 38041 Grenoble CEDEX (France)
4. DRFMC, Centre d'Etudes Nucleaires de Grenoble, Boite Postale 85X, 38041 Grenoble CEDEX (France)
5. Department of Radiation Sciences, P.O. Box 535, S-75121 Uppsala (Sweden)
6. Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, Institut National de Physique Nucleaire et de Physique des Particules, Centr

Measurements of neutron yields and their angular distributions in coincidence with fission fragments produced in antiproton annihilation at rest in a natural uranium target have been carried out Low Energy Antiproton Ring (LEAR) at CERN. A total of 16.3{plus minus}0.9 neutrons per annihilation have been found, distributed among direct knockout (27%), evaporation (21%), and fission (52%) processes. Angular distributions show that neutrons below approximately 5 MeV result entirely from moving fission fragments, and above approximately 12 MeV entirely from the excited, prescission nucleus. An estimate of the angular momentum of the excited fission fragment gives {similar to}13{h bar}. We are able to account for all baryons produced in annihilation, including neutrons from this experiment and light charged nuclei found in another LEAR experiment, to within 4.5{plus minus}2.5 of the initial 237 units in the initial state.

• OSTI ID: 7301093
• Journal Information: Physical Review, C (Nuclear Physics); (United States), Journal Name: Physical Review, C (Nuclear Physics); (United States) Vol. 45:5; ISSN 0556-2813; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

663470* -- Fission-- (1992-)
663590 -- Nuclear Mass Ranges-- A=220 & Above-- (1992-)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACTINIDES
ANGULAR DISTRIBUTION
ANNIHILATION
ANTINUCLEON REACTIONS
ANTIPROTON REACTIONS
BARYON REACTIONS
BARYONS
BASIC INTERACTIONS
DISTRIBUTION
ELECTROMAGNETIC INTERACTIONS
ELEMENTARY PARTICLES
ELEMENTS
FERMIONS
FISSION
FISSION FRAGMENTS
HADRON REACTIONS
HADRONS
INTERACTIONS
METALS
NEUTRON SPECTRA
NEUTRONS
NUCLEAR FRAGMENTS
NUCLEAR REACTIONS
NUCLEON REACTIONS
NUCLEONS
PARTICLE INTERACTIONS
SPECTRA
URANIUM