|Author||Bercovitch, M. ♦ Carmichael, H. ♦ Hanna, G. C. ♦ Hincks, E. P.|
|Source||United States Department of Energy Office of Scientific and Technical Information|
|Subject Keyword||PHYSICS ♦ ALPHA DECAY ♦ BERYLLIUM ♦ BORON 10 ♦ BORON FLUORIDES ♦ CHERENKOV COUNTERS ♦ CONTAMINATION ♦ COSMIC RADIATION ♦ CROSS SECTIONS ♦ EFFICIENCY ♦ ENERGY ♦ ENERGY RANGE ♦ ERRORS ♦ EVAPORATION ♦ FISSION ♦ INTERACTIONS ♦ LEAD ♦ LIQUIDS ♦ MEASURED VALUES ♦ MODERATORS ♦ MONTE CARLO METHOD ♦ MUONS ♦ NEUTRON DETECTION ♦ NEUTRON SOURCES ♦ NEUTRONS ♦ NITROGEN ♦ PARAFFIN ♦ PERFORMANCE ♦ PLATES ♦ PLEXIGLAS ♦ PLUTONIUM 240 ♦ POLYMERS ♦ PRODUCTION ♦ PROTONS ♦ RADIUM ♦ STANDARDS ♦ TARGETS ♦ THICKNESS ♦ TIN ♦ TUNGSTEN ♦ URANIUM ♦ WATER|
|Abstract||The production of low-energy neutrons in U, Pb, W, and Sn by protons of six selected energies between 250 and 900 Mev was measured using cosmic radiation as a proton source. The protons were selected and their energy measured by a vertical counter telescope containing three Cherenkov detectors which employed liquid nitrogen, water, and Plexiglas as radiating media. The protons interacted in 22 and 44 g cm/sup 2/ thick slabs of the target elements, and the neutrons produced were detected in a 4-foot cubic paraffin moderator, B/sup 10/F/sub 3/ counter assembly placed below the proton selecting telescope. The principal body of data was obtained at 3260 m altitude; a series of runs at 150 m was made to check the high-altitude data for muon contamination of the selected protons. The proton-gated neutron rates for the various targets were converted to mean neutron muitiplicities per interaction using (a) the efficiency of the neutron detector as measured using calibrated Pu/sup 240/ spontaneous fission and Ra- alpha -Be neutron sources (b) the interaction cross sections of Chen, Leavitt, and Snapiro. The mean multiplicities per interaction range from 5.8 combination rat 1.0 for 300-Mev protons on 33 g cm/sup -2/ thick Sn, to 26.7 combination rat 4.2 for 820- Mev protons on 44 g cm/sup -2/ thick U. The multiplicities predicted from the Monte Carlo nucleon cascade calculation of Metropolis et al. and the Monte Carlo evaporation calculation of Dostrovsky et al. are in agreement with the measurements when secondary neutron prcduction in the thick targets is taken into account. (auth)|
|Learning Resource Type||Article|
|Publisher Department||Atomic Energy of Canada Ltd., Chalk River, Ont.|
|Organization||Atomic Energy of Canada Ltd., Chalk River, Ont.|
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