Study of a multiwire proportional chamber as high count rate X-ray detector

A multiwire proportional chamber of novel design has been built to study the feasibility of the chamber to measure high intensity X-rays. The well collimated X-ray beam was made to pass into the chamber parallel to the planes of electrodes and perpendicular to the direction of the anode wires. The chamber was tested using X-rays of energies 5.9 keV and 6.9 keV. The shift of the pulse height distribution with the increase of count rate indicated that space charge limits the count on a single wire to about 105 per s. A count rate of about 7×105 per s was obtained using 25 wires. The energy resolution of the chamber was also found to deteriorate at high count rate. The X-ray absorption coefficient in a 90% argon, 10% methane gas mixture at atmospheric pressure has been found to be 283 cm2/g for X-rays of energy 5.9 keV.