Bruker AXS B.V.^* Bruker AXS Inc., Madison WI, USA^**
○Martin Adam^* Matt Benning^** Yacouba Diawara^** Roger Durst^** Bram Schierbeek^*

Axiom 200: A new type of imaging detector for X-ray crystallography based on resistive microgap technology will be described. The Axiom 200 exhibits a number of compelling advantages over the conventional, analog detectors such as CCD's and image plates. The Axiom 200 is a pure digital photon-counter and thus exhibits true single-photon sensitivity with essentially zero intrinsic noise and zero frame readout dead time. This allows it to acquire both very long exposures on weakly diffracting samples without data degradation and also extremely fast exposures for time resolved experiments. It also demonstrates a very high counting rate. With an active area of 20 cm and a spatial resolution better than 100 microns the Axiom 200 can resolve over 400 diffraction orders. Also, the Axiom 200 is extremely robust and has no internal dead areas. Because of the short read-out time the Axiom can be used in shutter-free mode, where the shutter is only opened once at the start of the experiment and closed again at the end of the experiment. The high sensitivity and low noise make the Axiom 200 a good candidate for SAD phasing experiments. Results of high quality data collections and successful S-SAD phasing will be shown.