ELETTRA

SYNCHROTRON RADIATION SOURCE IN TRIESTE

Elettra (www.elettra.trieste.it) is the Italian third generation synchrotron radiation laboratory. It is built around a medium energy electron storage ring operated at 2 and 2.4 GeV. The Elettra beamlines cover a wide energy range, from the far infrared to the hard x-rays, with wavelengths between 0.6 mm and 0.3 Å.

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Beamlines at ELETTRA

The facility is operated by the Sincrotrone Trieste public no profit company, which built the accelerator system and some of the beamlines. Other beamlines are built in collaboration with external partners from various scientific institutions, both Italian and from other countries. All together there are 15 operating beamlines and 4 under commissioning.

Elettra also hosts several support and complementary laboratories, which make it a multidisciplinary research and service centre, competitive at the international level. Researchers at Elettra are active in fields as diverse as genomics, pharmacology, biomedicine, catalysis and chemical processes, microelectronics and micromechanics.

The X-Ray Diffraction 1 beamline has been designed primarily for macromolecular crystallography. The light source is a multipole wiggler with a useful range from 4 to 25 keV. The optics consists of a double-crystal monochromator in non-dispersive configuration, followed by a toroidal focussing mirror with a horizontal acceptance of 2.8 mrad. The tunability of the wavelength provides the opportunity to use the MAD technique for solving the phase problem over a broad range of wavelengths, covering the absorption edges of all heavy atoms commonly used in protein crystallography. The multipole wiggler spectrum includes high photon flux at low energies, allowing optimisation of the anomalous signal at the Sulphur, Xenon and Calcium edges.

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CCD on the diffraction beamline, with He purging path for long wavelength data collection (photograph by K. Djinovic)

The high-flux Small Angle X-ray Scattering beamline is mainly intended for time-resolved studies on fast structural transitions in the sub-millisecond time region in solutions and partly ordered systems with a SAXS-resolution of 1 to 140 nm in real-space. The SAXS-Beamline accepts 3 discrete energies, namely 5.4, 8 and 16 keV (0.077, 0.154, 0.23 nm). The beamline optics consists of a flat, asymmetric-cut double crystal monochromator and a double focusing toroidal mirror.

At present the X-ray Absorption Fine Structure (XAFS) beamline is under commissioning.

Giorgio Paolucci, Riccardo Spagna and Augusto Pifferi