Multi-wire proportional counters with delay line readout are the standard detectors in use on small angle X-ray diffraction beam lines at the Synchrotron Radiation Source (SRS). Their sensitivity and speed of readout would make them a desirable detector for large angle diffraction stations if it were not for the image distortion caused by 'parallax smearing'. This aberration occurs because of the large range of path lengths prior to interaction in the gas for the photon energies of interest similar to 10 keV (1.2 Angstrom). A potential solution to this problem is the secondary electron emission (SEE) detector in which the secondary electrons from photoelectric interactions in a thin layer of suitable material are detected, Detectors based on this principle have been successfully built, and demonstrated at the ESRF. However, their detection efficiency is poor due to the low escape probability of the secondary electrons from the photoconverter. The SRS detector group in collaboration with the University of Leicester Physics and Astronomy department, have attempted to use a CsI coated microchannel plate as the photo-converter. It was initially thought that a carefully designed MCP might improve upon the efficiency of a single layer of material. When run at very low gain the MCP has been shown to be capable of operating in a low pressure MWPC with a standard readout system. An MCP designed for soft X-ray detection was used in this preliminary study and the detection efficiency was found to be poor. Alternative MCP designs are discussed.

Multiwire proportional counters (MWPCs) have been used regularly on the Synchrotron Radiation Source (SRS) at Daresbury. They are photon counting, can cover large areas, and have fast readout times which makes them attractive to study dynamic processes such as muscle contraction. However, their operation at high rates has been a major limitation, due to two factors, space charge in the detector reducing the local count rate capability, and slow readout electronics which reduces the global count rate.The Daresbury biological X-ray detector group have developed a new type of detector called the wire microgap which significantly improves the local count rate capability of the detector. Coupled to this is a complex 1D electronic readout system which uses an amplifier and discriminator per wire and can handle charge spreading across two wires. The result is a 1D detector system 200 x 15 mm active area which can accept a global count rate of 200 MHz.This paper describes the design and performance of the detector and readout system and presents some results illustrating the fast framing capability of the detector which demonstrate a single shot timing sequence with a resolution of 50 mu s. Also presented are recent beamline results.