Technique for the evaluation of systematic errors in the activation analysis for oxygen with 14-Mev. neutrons

Abstract

In comparative 14-MeV neutron activation analysis of oxygen, the neutron and gamma ray attenuation differences in the sample and standard introduce systematic errors.A quantitative evaluation of these attenuation processes in a wide range of matrices and for three sample diameters is given. The experimentally determined correction factor, in each case, shows an exponential dependence on the calculated difference between the appropriate attenuation coefficients for sample and standard. Within the range

Use of a 60-Mev. linac for fast and variable-energy neutron activation analysis

“…The relative standard deviation given for the activation analysis data is ±10%. there is much room for improvement, for instance, none othe improvements worked out by the NBS group for fastf neutron activation analysis (7,8) have been used. At present, the detection limit for the fluorine determination for our method is 0.05% when one-gram sample is used.…”

Activation analysis section:

“…The evaluation of systematic errors in the analysis for oxygen was a major objective of further research [4] and methods were developed whereby accurate absorption correction factors could be experimentally determined with a high degree of precision. In comparative 14-MeV neutron activation analysis for oxygen, the neutron and gamma-ray attenuation differences in the sample and standard introduce systematic errors.…”

“…The equipment used and experimental procedure including sample selection and preparation are outlined in detail [4]. The experimentally deter- [5].…”

“…By the judicious selection of appropriate samples and standards, the reaction threshold effect on the previously determined neutron attenuation correction relationship [4] and the photon energy dependency on the attenuation correction factor were evaluated. For positron emitters, careful sample selection and preparation permitted a study of effects due to differences in density and positron energy or both.…”

“…Since the photon attenuation correction factors The samples were irradiated for about thirty seconds with a standard in our dual sample-biaxial assembly, and the oxygen content determined by a method recently described [3,4] [6] and xanthine oxidase [7] respectively.…”