Detection of Fast Neutrons Using Threshold Activation Reactions

6 DETECTION OF FAST NEUTRONS USING THRESHOLD ACTIVATION REACTIONS 

Detection of fast neutrons by threshold activation reactions (or threshold detectors) is based on the existence of an energy threshold for certain reactions of neutrons with nuclei. Thus, if one activates a foil made of such nuclei, the activity of the foil will give a measure of the neutron flux above the threshold. 

The main advantages of this technique, over the use of otheT spectrometers, are as follows  

The foils have a small volume and a low cross section therefore, they do not disturb the neutron field. 

Their small size makes the location of foils possible in places where no other spectrometer would fit. 

---