Development of New Type Boron-coating Proportional Counter and Its Experimental Investigation and Simulation Calculation

Three materials wherein suitable proportion of isotope enriched ¹⁰B powder, 1,2-ethylene dichloride and formvar resin were blended to make ¹⁰B neutron sensitive coating by oneself. A new type proportional counter that coated with ¹⁰B neutron sensitive coating was made. Furthermore, in order to increase the character and quality of the neutron detector, a set of 14 annulus epoxy sheets which were sided with ¹⁰B film were placed in the tube. A series performance tests were done by ²⁴¹Am-Be neutron source. The tests of 3.7×10⁹ Bq ²⁴¹Am-Be neutron source show that the plateau length of detector is 150 V from 750 V to 900 V, while the plateau slope is 8.2%/100 V. When the working voltage is 800 V, the count rate of new type boron-coating proportional counter is 50 s^-1. The level of sensitivity is 0.71 cm². Compared with the detector only coated with ¹⁰B film in the inner walls of detector, neutron sensitity area of the new detector increases to 3.15 times. The results show that the plateau length increases from 80 V to 150 V, and the plateau slope is improved from 12.4%/100 V to 7.58%/100 V, while the neutron sensitivity increases to 2.63 times. Using Geant4 software based on Monte Carlo method, this paper presented the response and detection efficiency of new type boron-coating proportional counter, which was covered with 55 mm×250 mm cylinder high density polyethylene moderator material. The simulation results of Geant4 are in agreement with the results of ²⁴¹Am-Be neutron source experiment.It shows the reliability of simulation application.