SIMPLE FLOW PROPORTIONAL DETECTOR FOR SOFT X-RAYS

A simple small (5 cm long) flow proportional detector for soft x rays is described. The detector is constructed from 3.175 cm hexagonal aluminum bar stock. The detector window is cut in one face of the bar and the ultrathin window seals on that face. O-ring construction is used to allow easy replacement of the 0.00254 cm tungsten wire. The operation of the detector at subatmospheric pressure in a high vacuum chamber is described. Vacuum and gas connections to the detector and to a manometer are shown which allow operation at 100-150 Torr with reference to the chamber pressure. Operating voltage using P-10 gas and counting monochromatic Al Kα at 8.34 Å is 950 V at 150 Torr and 1750 V at 760 Torr. © 1969 The American Institute of Physics.