CROSS SECTIONS OF THRESHOLD REACTIONS FOR FISSION NEUTRONS: NICKEL AS A FAST FLUX MONITOR

Journal Article · Tue Aug 01 04:00:00 EDT 1961 · Nuclear Sci. and Eng.

OSTI ID:4843362

Passell, T O; Heath, R L

Measured values of effective cross sections for fission neutrons obtsined for (n,p) reactions on Ni/sup 58/ Fe/sup 54/, Zn/sup 64/ Mg/sup 24/, Fe/ sup 56/, Zn/sup 67/, and Cu/sup 65/ are 92, 54, 28, 1.2, and 0.36 mb, respectively. All cross sections are based upon the value 0.60 mb for the (n alpha ) reaction on Al/sup 27/. Measurements are made at the exact center of the EBR-I core. This pcsition is to have a neutron energy spectrum similar to that of virgin fission neutrons in the region above 2 Mev. The (n,p) reaction on Ni/ sup 58/ is shown to have unusual practical advantages as a fast flux monitor. The chemical and physical stability of nickel metal in most reactor coolants, the absence of radioactivities obscuring the daughter Co/sup 58/, the long half life of Co/sup 58/ (72 days), and the ease with which its 0.800 Mev gamma can be measured, are some of these advantages. A major but avoidable drawback is the 1650 barn thermal neutron capture cross section of Co/sup 58/. A comparison of nickel and sulfur in measuring fast neutron flux spectra is included. Evidence is presented that indicates that the fission neutron cross section of S/sup 32/ is 65 mb. (auth)

• Research Organization: Stanford Research Inst., Menlo Park, Calif.; Phillips Petroleum Co., Idaho Falls, Idaho
• NSA Number: NSA-15-028539
• OSTI ID: 4843362
• Journal Information: Nuclear Sci. and Eng., Journal Name: Nuclear Sci. and Eng. Vol. Vol: 10
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ALPHA PARTICLES
ALUMINUM 27
COPPER 65
CROSS SECTIONS
EBR-1
ENERGY
FAST NEUTRONS
FISSION PRODUCTS
IRON 54
IRON 56
MAGNESIUM 24
MEASURED VALUES
NICKEL 58
NUCLEAR REACTIONS
PHYSICS
REACTOR CORE
REACTORS
SPECTRA
STANDARDS
TARGETS
ZINC 64
ZINC 67