Multigroup antiproton transport and fission

Journal Article · Fri Jan 01 04:00:00 EST 1993 · Nuclear Science and Engineering; (United States)

OSTI ID:6430460

Wienke, B R; Seamon, R E; Madland, D G ^[1]

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1. Los Alamos National Lab., NM (United States)

Antiprotons are negatively charged protons that continuously slow down in matter until they are stopped and captured on the surface of a nucleus by a proton; in which case, both proton and antiproton annihilate into gammas, pions, and other short-lived particles. When an antiproton annihilates at rest on the surface of an actinide nucleus, such as uranium, many fragments and neutrons are also produced, following direct reaction, nuclear evaporation, and fission processes, along with production of high-energy gammas and pions. Collectively, these processes have been termed antiproton fission, for simplicity, because many neutrons are produced as the end result of all reactions. Recent experiments at CERN suggest that as many as 15 to 20 neutrons ar emitted following antiproton annihilation on [sup 238]U, that their distribution is peaked near 5 MeV in energy, and that a sizeable fraction (45 to 75%) of the annihilation energy (1.88 GeV per annihilation) is deposited locally in the [sup 238]U. A fit to the experimental neutron spectrum of Angelopoulos et al. is presented, and the systematics of transporting and annihilating antiprotons in a multigroup representation are investigated for the first time. Applications of antiproton transport and fission in small spherical assemblies are discussed and contrasted, mainly systematics of local and nonlocal antiproton annihilation, criticality, and disassembly.

• OSTI ID: 6430460
• Journal Information: Nuclear Science and Engineering; (United States), Journal Name: Nuclear Science and Engineering; (United States) Vol. 113:1; ISSN NSENAO; ISSN 0029-5639
• Country of Publication: United States
• Language: English

Related Subjects

663430* -- Nucleon-Induced Reactions & Scattering-- (1992-)
663590 -- Nuclear Mass Ranges-- A=220 & Above-- (1992-)
663620 -- Physics of Radiations Other Than Neutrons-- (1992-)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANNIHILATION
ANTIBARYONS
ANTIMATTER
ANTINUCLEI
ANTINUCLEON REACTIONS
ANTINUCLEONS
ANTIPARTICLES
ANTIPROTON REACTIONS
ANTIPROTONS
BARYON REACTIONS
BARYONS
BASIC INTERACTIONS
CHARGED-PARTICLE TRANSPORT THEORY
CRITICALITY
DIRECT REACTIONS
ELECTROMAGNETIC INTERACTIONS
ELEMENTARY PARTICLES
ENERGY DEPOSITION
EVAPORATION MODEL
FERMIONS
FISSION
HADRON REACTIONS
HADRONS
INTERACTIONS
MATHEMATICAL MODELS
MATTER
MULTIGROUP THEORY
NEUTRAL-PARTICLE TRANSPORT
NEUTRON SPECTRA
NEUTRON TRANSPORT
NEUTRON TRANSPORT THEORY
NEUTRONS
NUCLEAR MODELS
NUCLEAR REACTIONS
NUCLEI
NUCLEON REACTIONS
NUCLEONS
PARTICLE INTERACTIONS
RADIATION TRANSPORT
SPECTRA
TARGETS
TRANSPORT THEORY
URANIUM 238 TARGET