Developments in optics and performance at BL13‐XALOC, the macromolecular crystallography beamline at the Alba Synchrotron. (19th May 2014)

• Record Type: Journal Article
• Authors: Juanhuix, Jordi; Gil‐Ortiz, Fernando; Cuní, Guifré; Colldelram, Carles; Nicolás, Josep; Lidón, Julio; Boter, Eva; Ruget, Claude; Ferrer, Salvador; Benach, Jordi
• Is Part Of: Journal of synchrotron radiation. Volume 21:Part 4(2014)
• Page Start: 679
• Page End: 689
• Publication Date: 2014-05-19
• Subjects: Synchrotron radiation -- Periodicals; Free electron lasers -- Periodicals; 539.73505
• DOI: 10.1107/S160057751400825X
• Languages: English
• ISSNs: 0909-0495

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>BL13‐XALOC is currently the only macromolecular crystallography beamline at the 3 GeV ALBA synchrotron near Barcelona, Spain. The optics design is based on an in‐vacuum undulator, a Si(111) channel‐cut crystal monochromator and a pair of KB mirrors. It allows three main operation modes: a focused configuration, where both mirrors can focus the beam at the sample position to 52 µm × 5.5 µm FWHM (H × V); a defocused configuration that can match the size of the beam to the dimensions of the crystals or to focus the beam at the detector; and an unfocused configuration, where one or both mirrors are removed from the photon beam path. To achieve a uniform defocused beam, the slope errors of the mirrors were reduced down to 55 nrad RMS by employing a novel method that has been developed at the ALBA high‐accuracy metrology laboratory. Thorough commissioning with X‐ray beam and user operation has demonstrated an excellent energy and spatial stability of the beamline. The end‐station includes a high‐accuracy single‐axis diffractometer, a removable mini‐kappa stage, an automated sample‐mounting robot and a photon‐counting detector that allows shutterless operation. The positioning tables of the diffractometer and the detector are based on a novel and highly stable design. This equipment, together with the operation flexibility of the beamline, allows a large variety of types of crystals to be tackled, from medium‐sized crystals with large unit‐cell parameters to microcrystals. Several examples of data collections measured during beamline commissioning are described. The beamline started user operation on 18 July 2012.</p> </abstract>