= 108 Sey, This instrument however, has its pulses produced by the neutron of a reaction with boron in the filling and as a result, it's responses is essentially flat down to neutron energies of about 10 KEV. Now, the biacing circuit is de- signed then, to accept pulses which are greater than the minimum to discriminate be- tween ambient nolee and radiation of other types. There's another way in which you can fail to diccriminate between neutron radiation and radiation - well, specifically ganma radiation and this is in the case known as gamma "pylo®, This 19° desipned on the asecumption that the incoming pulses can be meoognized ag individual events. This ia the bias level. Now, ordi- narily, if they come in, the neutron pulse might look like that roughly -- if the instantaneous dose rate is sufficiently large, they are no longer resolved into individual events and the gamma rate; pulse height then, is the sum of the individual pulse heights produced and as a result, may override the bias and be counted as a neutron pulce,