As I have posted many time before on the old listing the BC-720 by Bicron is about .6 % efficient at detecting 2.45 mev neutrons. So for every 166 neutrons entering the volume of the detector, only one will produce the flash of light from the phosphor. I am sure the hornyak button will be much less efficient than this.
The main advantage of the BC-720 is that it is Gamma immune and produces easily discriminated pulses into the PMT.
Richard Hull
Created on Monday, January 15, 2001 10:09 AM EDT by Richard Hull