Threshold Reaction Interference in Neutron Activation Analysis

Technical Report · Mon Jan 01 04:00:00 EST 1962

OSTI ID:4801011

Durham, R W; Navalkar, M P; Ricci, E

The high energy (>0.5 Mev) component of a reactor flux can produce, via threshold reactions on the major constituents of a sample, identical activities as those produced by the thermal flux, through (n, gamma ) reactions, on the impurities being determined. In order to predict these interferences in thermal neutron activation analysis, it is necessary to know: the cross section of the threshold reaction in a pure fission neutron flux; and, the fraction of the reactor thermal flux, nv/sub o/, above about 0.5 Mev which has the properties of a pure fission flux. The latter was determined in an empty fuel rod position tn the NRX reactor using the reaction U-238 (n,f) as a monitor. Based on this value, fission neutron cross sections were measured for several (n,p) (n, alpha ), (n,2n), and (n,n') reactions. The interferences caused by the (n,p) and (n, alpha) reactions in this particular irradiation position are given. An example of activation by (n,2n) and (n,n) reactions, when the (n, gamma) reaction is not suitable, is also discussed.(auth)

• Research Organization: Atomic Energy of Canada Ltd., Chalk River, Ontario (Canada)
• NSA Number: NSA-16-011512
• OSTI ID: 4801011
• Report Number(s): CRDC-1070; AECL-1434
• Country of Publication: Canada
• Language: English

Related Subjects

ACTIVATION ANALYSIS
ALPHA PARTICLES
CHEMISTRY
CROSS SECTIONS
ENERGY LEVELS
FERMIONS
GAMMA RADIATION
IMPURITIES
MONITORING
NESDPS Office of Nuclear Energy Space and Defense Power Systems
NEUTRON BEAMS
NRX
NUCLEAR REACTIONS
PROTONS
THERMAL NEUTRONS
URANIUM 238