Inclusive neutron production by 337 MeV/nucleon neon ions on carbon, aluminum, copper, and uranium

R. A. Cecil, B. D. Anderson, A. R. Baldwin, R. Madey, W. Schimmerling, J. W. Kast, and D. Ortendahl
Phys. Rev. C 24, 2013 – Published 1 November 1981
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Abstract

We measured inclusive double-differential cross sections at angles of 30, 45, 60, and 90 deg for the production of neutrons above about 12 MeV from 337 MeV/nucleon neon ions bombarding targets of C, Al, Cu, and U. Three different energy regions can be distinguished in the neutron spectra: (1) a low-energy "evaporation" region, (2) a high-energy exponential tail reflecting the internal momentum distribution of the nucleons, and (3) an intermediate energy region reflecting quasifree and preequilibrium processes. The intermediate-energy region becomes less pronounced with increasing angle and is almost nonexistent at 90 deg. This behavior is consistent with the interpretation that the intermediate-energy region consists mainly of scattering processes with a few direct collisions. The intermediate-energy region is relatively flat at the forward angles and merges into an exponential falloff at wide angles. The 30-deg spectrum from the carbon target shows a broad peak around 150 MeV, which we interpret as a signature of quasifree nucleon-nucleon collisions. Although the neutron detection threshold does not permit us to see the evaporation peaks, we do see evidence of the evaporation tails. The evaporation yields apparent in our spectra increase with the mass number of the target. The neutron spectra differ from proton spectra reported for similar targets at 385 and 393 MeV/nucleon. The neutron-to-proton cross section ratios are fit well by an intranuclear-cascade model calculation, but poorly by a "firestreak" model calculation.

NUCLEAR REACTIONS C, Al, Cu, U(Ne, nX), E=337 MeV/nucleon. Measured double-differential cross sections at θlab=30, 45, 60, and 90 deg. Deduced total integrated neutron cross sections above 25 MeV. Compared neutron spectra with proton spectra and neutron/proton cross section ratios with the firestreak model.

  • Received 4 May 1981

DOI:https://doi.org/10.1103/PhysRevC.24.2013

©1981 American Physical Society

Authors & Affiliations

R. A. Cecil, B. D. Anderson, A. R. Baldwin, and R. Madey

  • Department of Physics, Kent State University, Kent, Ohio 44242

W. Schimmerling, J. W. Kast*, and D. Ortendahl

  • Lawrence Berkeley Laboratory, Berkeley, California 94720

  • *Present Address: Varian Associates, Palo Alto, California 94303.
  • Present Address: UCSF - RIL, South San Francisco, California 94080.

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Vol. 24, Iss. 5 — November 1981

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