MEASURING METHOD FOR LIQUID LEVEL N TUBE BY MEANS OF NEUTRON

摘要

PURPOSE:To increase a counting rate ratio by counting neutrons with a thermal neutron counter tube surrounded by cadmium after counting them with the thermal neutron counter tube not surrounded by cadmium. CONSTITUTION:A level of liquid surface 5 of reserved liquid 3 inside a liquid reservoir tube 4 to be measured is measured. First, a neutron beam source 8 coated by high density polyethylene 6a and cadmium 7a is inserted into a tube 2a in which gas flows on the left of the tube 4b to be measured. Then a thermal neutron counter tube 9 is inserted into a tube 2b where gas flows on the right of the tube 4b to be measured while the tube 9 is not surrounded by cadmium 7b to measure the level of the liquid surface 5. Then the thermal neutron counter tube 9 is inserted into the tube 2b to be measured while it is surrounded by cadmium 7b to measure the level of the liquid surface 5. Thus disturbance due to neutrons having higher energy than thermal neutrons can be removed thereby largely improving a counting rate ratio.