Determination of hydrogen content in bulk samples using the neutron activation method

An improved method for bulk hydrogen analysis using epithermal neutrons

The advantages of direct detection of thermalized neutrons as compared to the activation method used for bulk hydrogen analysis have been investigated. In both cases samples of 10 cm diameter and 8 cm height dimensions were used. It was found that the new method based on a small BF(3) counter placed along the central line of the cylindrical samples renders the determination of hydrogen contents routinely possible using a few minutes measuring time and a low intensity ( approximately 18.5 GBq) neutron source. A preliminary investigation has shown that the direct detection of neutrons can be used for analysis of samples as large as about 20l. Details of this technique and its applications will be discussed in the next paper.

A comparison of the neutron thermalization and reflection methods used for bulk hydrogen analysis

The advantages and limitations of the slowing down of epithermal neutrons and the thermal neutron reflection methods were compared for bulk hydrogen analysis. In both cases, the same sample dimensions were used, i.e. 10cm diameter and 8cm height. It was found that the sensitivity of the slowing down method is higher by a factor of approximately 20 in average and the matrix effect can be neglected as compared to the neutron reflection technique. The simultaneous application of the two methods renders the determination of the H content and the C/H atomic ratio possible. The effect of spatial distribution of hydrogen in the matrix to be investigated on the number of reflected neutrons was also studied.