Selector for fast and intermediate energy neutrons positioned within moderator and absorber shields

Claim 1

APPARATUS FOR MEASURING BIOLOGICAL DOSAGE FROM A SOURCE OF FAST AND INTERMEDIATE NEUTRONS COMPRISING MEANS FOR DETECTING NEUTRONS SUBSTANTIALLY ONLY IN THE THERMAL ENERGY RANGE, SAID DETECTING MEANS BEING POSITIONED WITH ONE END FOR RECEIVING SAID NEUTRONS FROM SAID SOURCE, COMPENSATING SHIELD MEANS INCLUDING BOTH A NEUTRON ABSORBING AND SLOWING MATERIAL POSITIONED BETWEEN SAID SOURCE AND SAID END AND SUBSTANTIALLY ENCLOSING AND CONTIGUOUS WITH SAID END, SAID SLOWING MATERIAL HAVING ONE LAYER POSITIONED BETWEEN SAID END AND SAID ABSORBING MATERIAL AND HAVING ANOTHER LAYER POSITIONED BETWEEN SAID ABSORBING LAYER AND SAID SOURCE, THE RELATIVE THICKNESS OF SAID LAYERS BEING SUCH THAT LOW ENERGY NEUTRONS FROM THE SOURCE ARE ABSORBED WHILE HIGH ENERGY NEUTRONS ARE SLOWED AS THEY PASS THROUGH THE SHIELD AND THE DETECTOR MEASURES A QUANTITY DEPENDENT UPON THE ENERGY LEVEL OF THE NEUTRONS IN PROPORTION TO THE DOSAGE RECEIVED.