Neutron-fragment coincidence measurements in /sup 14/N+Ho and /sup 14/N+Ni reactions at 35 MeV/nucleon

Journal Article · Sat Nov 01 04:00:00 EST 1986 · Phys. Rev. C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.34.1685· OSTI ID:7166392

Remington, B A; Caskey, G; Galonsky, A; Gelbke, C K; Heilbronn, L; Heltsley, J; Tsang, M B; Deak, F; Kiss, A; Seres, Z; others, and

We have studied /sup 14/N+ /sup 165/Ho and /sup 14/N+Ni collisions at 35 MeV/nucleon by detecting neutrons at ten angles from 10/sup 0/ to 160/sup 0/ in coincidence with light fragments at six angles between 7/sup 0/ and 30/sup 0/. For a given fragment, the seven spectra of coincident neutrons whose angles are not near the fragment angle were fitted with two moving, thermal sources. One source is a slowly-moving, targetlike source; the other is a faster (approximately half-beam-velocity), hotter source. The latter source, an intermediate-rapidity source, reproduces a left-right asymmetry in which the fragment-neutron cross sections are larger for emission to opposite sides of the beam axis than for emission to the same side. The temperature of the targetlike source is about 3.5 MeV with the Ni target and about 2.5 MeV with the Ho target. The corresponding values for the intermediate-rapidity source are 10 and 8.5 MeV. These source temperatures are approximately independent of fragment angle, but the measured neutron multiplicities increase with fragment angle. For the targetlike source the largest multiplicities, 1.6 for Ni and 9 for Ho, are about (3/4) the values computed with a statistical code. The multiplicities of the intermediate-rapidity source are about (1/4) the multiplicities of the targetlike source. The necessity for an intermediate-rapidity source is also demonstrated in terms of ''missing momentum'' in the final state of an assumed two-body, /sup 14/N+target inelastic collision. The mass number of this source is estimated in peripheral collisions and in central collisions. The approximate independence of source parameters on fragment angle may indicate that the neutrons and the fragments are emitted at different times during the reaction.

• Research Organization: National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824
• OSTI ID: 7166392
• Journal Information: Phys. Rev. C; (United States), Journal Name: Phys. Rev. C; (United States) Vol. 34:5; ISSN PRVCA
• Country of Publication: United States
• Language: English

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR DISTRIBUTION
BARYONS
CHARGED-PARTICLE REACTIONS
COINCIDENCE SPECTROMETRY
DISTRIBUTION
ELEMENTARY PARTICLES
ELEMENTS
ENERGY RANGE
FERMIONS
HADRONS
HEAVY ION REACTIONS
HOLMIUM 165 TARGET
INELASTIC SCATTERING
MATHEMATICAL MODELS
METALS
MEV RANGE
MEV RANGE 100-1000
MULTIPLICITY
NEUTRONS
NICKEL
NITROGEN 14 REACTIONS
NUCLEAR FRAGMENTS
NUCLEAR REACTIONS
NUCLEONS
PARTICLE PROPERTIES
PARTICLE RAPIDITY
SCATTERING
STATISTICAL MODELS
TARGETS
TRANSITION ELEMENTS