A comparison of neutron-activation analysis and hot extraction analysis of the oxygen content of steel.
A system developed for the fast neutron-activation analysis of the oxygen content of metals has been tested comparatively with the conventional vacuum fusion and carrier-gas fusion techniques. The results of these tests indicate that neutron-activation analysis is much faster (the total analysis takes only 2 min or less), and more reliable than vacuum fusion and carrier-gas fusion methods because all oxygen present is analysed. Samples can be much larger than the 0.2-3 g commonly used for the fusion methods. Furthermore, the analysis is non-destructive-the same samples can be re-analysed as often as desired. The fast neutron-analysis system includes a 14-MeV neutron generator producing 10(11) neutrons/sec, a dual-tube pneumatic transfer system, a 5 x 5 inch NaI(T1)crystal, a single-channel analyser, two scalers, and timers and switch-gear. A sample, in a polyethylene bottle, and a Lucite reference are irradiated simultaneously, after which the sample is returned to a detector for counting the (16)N gammas from the (16)O(n,p)(16) N reaction. The reference is then counted in a second detector; the ratio of the sample counts to the reference counts is proportional to the oxygen content of the sample. Samples with oxygen contents from 0.002 to 0.1 % of oxygen have been analysed by neutron activation, then cut in several pieces for hot extraction analysis of the total sample.
Pasztor
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Graham Research Laboratory, Jones and Laughlin Steel Corporation Pittsburgh, Pennsylvania, U.S.A.
Wood
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