<b> 4th Workshop of High Resolution Diffraction at PETRA III</b>

On Oktober 29th 2009 the beamline P08 (HighRes) at the new 3rd generation synchrotron radiation source PETRA III had the first monochromatic beam at the experiment. Beamline P08 is optimized for high q-resolution experiments at photons in an energy range from 5.4keV up to 29.4keV. Three different modes are available which are realized by different focussing optics: The “raw mode” is relaxed in q-resolution but delivers the most intense beam. In the “collimating mode” the q-resolution is extraordinary good but at the expense of slightly less intensity. The “focussing mode” creates a 200µm x 20µm beam spot at the sample with a q-resolution comparable to the “raw mode”. Finally, at the “µ-mode” the beam size is approximately 20µm x 2µm. The intensity of the beam at the sample is in the range of 1e+11ph/sec up to 5e+12ph/sec depending on the photon energy and the selected mode. The higher harmonics suppression will be almost complete. The experimental hutch is equipped with the high precision multi circle diffractometer NZD-3 (made by Kohzu) for solid sample investigations and the liquid diffractometer LISA (made by University of Kiel) which allows scanning of angles or photon energy without moving the sample. Also, two motorized optical tables are available. At this workshop, user projects for HighRes will be presented and discussed (scientific talks or posters). The needs concerning a possible beamtime at P08 will also be addressed. The PETRA III HighRes team will present the performance of the PETRA III ring, the beamline optics and the infrastructure such as chemical labs and UHV preparation chambers. Contact: Oliver H. Seeck (oliver.seeck@desy.de) Carsten Deiter (carsten.deiter@desy.de)