An ultra-high counting rate 2D proportional counter for synchrotron radiation

Abstract Multiwire proportional counters are widely used in synchrotron radiation studies, for example in small angle diffraction experiments on biological systems. The active area and positional resolution of the detector can be conveniently matched to the dimensions of the synchrotron beam and to the optics of the beamline. Furthermore, the large dynamic range available from single photon counting systems is vital to exploit the true benefits of using synchrotron radiation for X-ray diffraction. The systems that are currently in routine use at the Daresbury SRS are based on the delay line method of position readout, a technique which inherently limits the count rate capability of the system to approximately 1 MHz. Large scale improvements in count rate performance require different readout systems which in general use many channels to improve throughput. A prototype high counting rate readout system has been constructed and commissioned. The system which is modular in nature and can therefore be tailored to particular applications, is described, and results are presented on its performance.