A NOVEL PROPORTIONAL COUNTER MADE OF A CAPILLARY PLATE

A new type of proportional counter utilizing a capillary plate with th e capability of fine position resolution and high gas gain has been de veloped. It consists of a bundle of fine glass capillaries with electr odes on both the inlet and the outlet. The capillaries are 100 mu m in diameter and 800 mu m in length, and gas multiplication was found to occur in each capillary with an applied voltage between the inlet and the outlet. The proportional counter was found to operate up to a gain of 10(4) at gas pressures of 1, 0.75 and 0.5 atm. The energy resoluti on for 1 atm was 20.8% for 5.9 keV X-rays at a gas gain of 4000. The d etection efficiency was comparable to a conventional single wire propo rtional counter. The dependences of energy resolution on the drift and applied-voltage to the capillary plate are investigated and discussed , using calculated electric fields for the drift and capillary regions .