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Abstract: At the free-electron laser user facility FLASH at DESY cesium telluride photocathodes are in use in the laser driven RF-gun based injector. We report on issues concerning quantum efficiency, lifetime, and dark current emission observed recently.

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Abstract: At Diamond Light Source [1] the three phase I macromolecular crystallography (MX) beamlines [2] have experienced their first year of user experiments. The current user programme is interspersed with commissioning and optimisation of the X-ray source (including automation of beam delivery) in conjunction with deployment and improvements in software and hardware to provide intuitive, state of the art MX beamlines. A large component of this work is to automate as many components and experimental processes as possible, from beam conditioning to user interaction. Aspects of automation of MX beamlines include tracking of information of protein crystal samples from before arriving on site, automounting and screening for crystal quality, collecting data and processing the results, and recording the results of all these steps. Of particular note, beamline I03, will provide biological containment category 3 facilities in the near future for work with pathogenic crystals at room temperature. Automation will be an essential component of this development, allowing tracking of crystals and the automounting of 1680 samples before decontamination of the working environment is required. Automation of the routine aspects of MX should aid both experienced and less experienced users and allow them to profit from their short time on the Diamond MX beamlines to maximise their scientific output. This suite of beamlines will provide an excellent environment for the collection of data from both cryogenic and room temperature crystals, using automation to guide the experiment rather than direct it. The current status of all aspects of automation on the phase I MX beamlines at Diamond Light Source will be presented.

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Abstract: Diamond Light Source has designed and constructed twelve permanent magnet insertion devices over the past five years. These are ten In-vacuum undulators and two Ex-vacuum Apple II undulators. For all of these a common control system has been used. This uses a VME based motor controller, and a separate PLC subsystem for protection. The VME system runs EPICS to integrate in with overall control system. Two new designs of Insertion Device are currently in progress, which will require variants of this control system. The design for these control systems, issues experienced, and operational performance will be presented.

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Abstract: The I12, Joint Engineering Environmental Process (JEEP) beamline is designed as a multi-purpose, high energy X-ray beamline providing flexibility in the type and complexity of the experiments it can accommodate. These will include ground breaking experiments to simulate the service conditions experienced by real engineering components, while their internal stress state and structures are continually monitored by the X-ray beam. In order to meet such demanding criteria, a monochromator capable of delivering a large cross section monochromatic beam, up to 100mm wide through an energy range of 50 – 150KeV is required. A cryo-cooled monochromator using a bent Laué-Laué geometry is being designed by the beamline team at Diamond. Of primary importance is the quality of the bend coupled with the thermal management. A typical bend radius of 60m +/-2m over the active area and a heat load of 750 W at 500 mA were specified by the science case. Detailed 3D Analysis of the design was performed combining thermo-mechanical finite element methods in order to see how the crystal would deform under such conditions. As part of the design cycle, the team at Diamond are building a prototype crystal assembly to prove the bending performance and validate the finite element analysis. Using a full field interferometer the surface of the bent crystal can be studied and verified against the perfectly circular geometry required in the Laué condition. Further testing with the monochromatic beam of B16 Optics beamline at Diamond will also be performed prior to final assembly of the I12 monochromator. JEEP is expected to take first light in March 2009 and the monochromator will be installed and operational ready to start taking beam at this time.

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Abstract: The effect of poly(ethylene glycol) PEG crystallization on P-sheet fibril formation is studied for a series of three peptide/PEG conjugates containing fragments modified from the amyloid P peptide, specifically KLVFF, FFKLVFF, and AAKLVFF. These are conjugated to PEG with M-n = 3300 g mol(-1). It is found, via small-angle X-ray scattering,X-ray diffraction, atomic force microscopy, and polarized optical microscopy, that PEG crystallinity in dried samples can disturb fibrillization, in particular cross-P amyloid structure formation, for the conjugate containing the weak fibrillizer KLVFF, whereas this is retained for the conjugates containing the stronger fibrillizers AAKLVFF and FFKLVFF. For these two samples, the alignment of peptide fibrils also drives the orientation of the attached PEG chains. Our results highlight the importance of the antagonistic effects of PEG crystallization and peptide fibril formation in PEG/peptide conjugates.