Neutron detection

Applications
1

Hello guys, this is more like a physics question.

So my task is to compute the neutron doses with the Bonner neutron detector at different distances from the AmBe source.

While reading some papers I noticed that people always start by plotting the response function of the detector vs the neutron energy and I am not sure I understand why. Are they doing it because, when they will measure their unknown source, G4 code will produce an output response from which they can obtain the average neutron energy of their particular source and then compute the dose? Does this response function represents the total number of He3(n,p)H3 reactions that were generated per neutron fluence (in the case of He-3 detector)?
For example, if I obtain 20 protons from 1000 neutrons that crossed the sphere’s surface, my detector response will be 20 and its efficiency 20/1000 ? Is this reasoning correct?

Please, any help is welcomed.

2

By pure chance, the response curve as a function of energy for a 12 inch Bonner sphere turns out to have a similar shape compared with the dose equivalent per neutron. So when the sphere is in a polyenergetic neutron field, the counts are automatically weighted for all energies, hence giving a meaningful estimate of the combined dose due to all the neutrons. Hence the need for calculating or measuring the response function.

Radiation Detection and Measurement by Glen F Knoll (pages 539-542 of the 3rd edition) gives a good explanation of such neutron moderation counters.

1 Like