ブックタイトル日本結晶学会誌Vol60No5-6

概要

日本結晶学会誌Vol60No5-6

Armin WAGNER，Ramona DUMAN，Kamel el OMARI，Vinay GRAMA，Vitaliy MYKHAYLYKHFig.2 a）Image of the a litholoop as attached to the I23sample holder. b）I23 sample holder with adaptor. c）Sample transfer block with 4 sample holders. d）I23sample holders on adaptors mounted on a unipuckbase for fast screening.using a modified version of the Leica VCT100 system. Foursamples can be transferred together per sample transfer block（Fig.2c）. The transfer block is pulled from a liquid nitrogenbath into the transfer shuttle. A radiation shield inside theshuttle is kept cold by liquid nitrogen after pumping theshuttle. An air-lock system allows the insertion of transferblocks into the sample hotel inside the vacuum end stationusing the shuttle while keeping the system under high vacuumconditions. 5 blocks with in total 20 samples can be kept inthe sample hotel. To mount crystals onto the goniometer,the sample hotel can be rotated into the pick-up position.A linear mechanism with a gripper is used to mount andunmount individual samples from the transfer blocks onto thegoniometer.Sample transfer into the vacuum end station and inside,from the sample hotel to the goniometer, is slow, hencespecial adaptors have been designed which are compatiblewith the BART robots 14）available at the high-throughputMX beamlines I03, I04 and I04-1. This allows very fast andefficient crystal pre-screening. The best crystals will then bere-sorted from the unipuck bases（Fig.2d）on I23 transferblocks（Fig.2c）.2.3 DetectorAs illustrated above, large diffraction angles have to beaccessible at longer wavelengths. The Pilatus 12M detectorcovers an angular range for diffraction experiments from 2θ＝－100°to＋100°. Initial long-wavelength and vacuum testsfor the Pilatus technology 15）were performed at the Diamondbeamlines I18 and B16, 16）followed by a full characterisationof the technology at BESSY2. 17）The detector, designedand built by Dectris（Baden, Switzerland）, consists of 120Pilatus2 modules arranged in a cylindrical geometry of 24banks of 5 modules. The sensor modules are located insidethe vacuum end station and are water-cooled to 12℃. 156individual electrical feedthroughs connect the sensor moduleswith the detector readout electronics in a box outside vacuumattached to the back of the end station vacuum vessel. Thedetector can be moved 250 mm along the beam, with thesample typically being placed on the cylinder axis.2.4 GoniometerAs for the detector, at the start of the project there was nocommercial system available for the I23 goniometer. Afterdiscussions with several companies and engineering groups,the I23 in-vacuum goniometer was commissioned to theAstronomy Technology Centre（ATC）, Edinburgh, UK. Theirlong-standing expertise in designing and building cryogenicpositioning systems was key to this project. The goniometer isbuilt in inverse kappa geometry 18）with an alpha angle ofα＝50°. To facilitate the thermal design with the flexible coppercooling links, the overall rotation ranges of the goniometerhad to be restricted for omega toω±270°, kappa toκ－10 to＋180°and phi toφ±180°.2.5 SoftwareData acquisition at Diamond MX beamlines is achievedusing the Generic Data Acquisition（GDA）system. 19）TheGDA system user interface is shared across all MX beamlinesand allows users to collect their datasets in a simple andhardware-safe fashion. More complex data collections suchas the inverse beam or using a multi-axis goniometer arealso easily utilisable. The latter type of data collections areboth exploited by the strategy software ASTRA, developedby Global Phasing Ltd., in order to maximise the chances ofcollecting the best dataset for anomalous phasing.Because the speed and the number of data collections havetremendously increased over the years, it is essential to beable to process datasets efficiently and quickly. Diamond hasimplemented a set of data processing pipelines using Xia2 20）and autoPROC, 21）utilising Dials 22）and XDS 23）for exhaustiveprocessing, but also fast-DP a near-real-time data processingsoftware for quick assessment of the data, A second seriesof pipelines（post-processing）enable automatic molecularreplacement against the collected data if a model is provided（DIMPLE）, 24）or structure solution by experimental phasingif some anomalous signal is detected（fast-EP and big-EP）. 25）Finally this overabundance of data needs to be easilyaccessible to users, hence a database ISPYB 26）and itsinterface‘synchweb’27）have been developed, to guide usersthrough their data collection and processing results. I23236日本結晶学会誌第60巻第5･6号（2018）