A CURVED MICRO-STRIP GAS COUNTER FOR SYNCHROTRON-RADIATION TIME-RESOLVED SAXS WAXS EXPERIMENTS/

We are constructing a positive-sensitive detector that is capable of d etecting an S-ray diffraction pattern with a count rate of up to 1 MHz per channel. The channel width is 0.4 mm. This detector is based on t he Micro-Strip Gas Counter (MSGC) technology. The detecting and conver ting medium is argon or xenon gas. The wedge-shaped substrates carry c harge-sensitive strips, which define detector channels in the counter gas pointing to the scattering centre, enabling parallax-free detectio n. A conversion range of 4 cm along the strips is available, so the ef ficiency is higher than for conventional designs, while the count rate per centimetre strip is lower. We present test results on the rate ca pability and the energy resolution for a prototype.