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A new undulator beamline (P22) for hard X-ray photoelectron spectroscopy (HAXPES) was built at PETRA III (DESY, Hamburg) to meet the increasing demand for HAXPES-based techniques. It provides four special instruments for high-resolution studies of the electronic and chemical structure of functional nano-materials and catalytic interfaces, with a focus on measurements under operando and/or ambient conditions: (i) a versatile solid-state spectroscopy setup with optional wide-angle lens and in-situ electrical characterization, (ii) a HAXPEEM instrument for sub-μm spectro-microscopy applications, (iii) an ambient pressure system (> 1 bar) for operando studies of catalytic reactions and (iv) a time-of-flight spectrometer as a full-field k-microscope for measurements of the 4D spectral function ρ(EB,k). The X-ray optics were designed to deliver high brightness photon flux within the HAXPES energy range 2.4 – 15 keV. An LN2-cooled double-crystal monochromator with interchangeable pairs of Si(111) and (311) crystals is optionally combined with a double channel-cut post-monochromator to generate X-rays with variable energy bandpass adapted to the needs of the experiment. Additionally, the beam polarization can be varied using a diamond phase plate integrated into the beamline. Adaptive beam focusing is realized by Be compound refractive lenses and/or horizontally deflecting mirrors down to a spot size of ~20x17 μm² with a flux of up to 1.1x1013 ph/s (for Si(111) at 6 keV). [ABSTRACT FROM AUTHOR]

The 3rd generation low-emittance 6 GeV PETRA III facility has been substantially modified to add new beamlines. This extension project involved the complete removal and reconstruction of part of the storage ring with a double-bend achromat lattice as well as the construction of two new experimental halls. Making use of two long straight sections and a canted undulator scheme in the rebuilt arcs, up to ten new insertion device beamlines can be accommodated. In the current phase of the project, seven insertion device and one bending magnet beamline are being implemented. [ABSTRACT FROM AUTHOR]

An instrument for high-energy X-ray photoelectron spectroscopy is operated at the BW2 wiggler beamline of HASYLAB. The photon energy ranges from 2.3 to 10 keV, the electron energy reaches up to 7.5 keV (including an optional 2.5 keV sample bias, the current electron analyzer limit is 5 keV). Using a Si(311) double crystal monochromator, the total energy resolution is 0.37 eV at 4.3 keV as determined from the Si 2p photoemission. For Si(111) typical values are 0.45 eV at 3 keV. The photon flux typically amounts to 5×1012 1/s for Si(111). Focusing is achieved by the combination of a sagittally bent monochromator crystal and a tangentially bent mirror in the monochromatic beam. The focus size (FWHM) at the sample is 0.25 mm (vertical) × 2 mm (horizontal) which is well matching the acceptance of the SCIENTA SES-200 electron analyzer. Selected results are shown to demonstrate the instrument performance. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

DESY in Hamburg, Germany, has decided to reconstruct its 2.304 km long storage ring PETRA II into a third generation synchrotron radiation source starting 2007. The synchrotron source will operate at 6 GeV particle energy, 100 mA current and an emittance of 1 nmrad. In the first phase thirteen independent undulator beamlines will be available for user experiments. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

Quadrupolar transitions can play an important role in X-ray absorption spectroscopy, especially when it is used for magnetic measurements, like in X-ray Magnetic Circular Dichroism or Resonant Magnetic Scattering. We show here that resonantly excited Ti KL[sub 2,3]L[sub 2,3] Auger spectra of TiO[sub 2] (110) carry a clear signature of quadrupolar transitions from the 1s to localized e[sub g] and t[sub 2g] d-like states. The quadrupolar nature of the observed additional spectator lines are clearly demonstrated by their angular dependence, and their intensity is used to locate and quantify the quadrupolar transitions in the absorption spectrum. [ABSTRACT FROM AUTHOR]