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München, Germany

Marcus G.,Max Planck Institute of Quantum Optics | Marcus G.,Hebrew University of Jerusalem | Helml W.,Max Planck Institute of Quantum Optics | Gu X.,Max Planck Institute of Quantum Optics | And 9 more authors.
Physical Review Letters | Year: 2012

Subfemtosecond bursts of extreme ultraviolet radiation, facilitated by a process known as high-order harmonic generation, are a key ingredient for attosecond metrology, providing a tool to precisely initiate and probe ultrafast dynamics in the microcosms of atoms, molecules, and solids. These ultrashort pulses are always, and as a by-product of the way they are generated, accompanied by laser-induced recollisions of electrons with their parent ions. By using a few-cycle infrared (λ 0=2.1μm) driving laser, we were able to directly excite high-energy (∼870eV) inner-shell electrons through laser-induced electron recollision, opening the door to time-resolved studies of core-level and concomitant multielectron dynamics. © 2012 American Physical Society.


Kuhn A.,BAM Federal Institute of Materials Research and Testing | Scharf O.,IAP Institute fur Angewandte Photonik E.V. | Scharf O.,IfG Institute for Scientific Instruments GmbH | Ordavo I.,PNSensor GmbH | And 7 more authors.
Journal of Analytical Atomic Spectrometry | Year: 2011

A new setup for fast spatially resolved measurements of elemental trace amounts under total reflection conditions using a new colour X-ray camera is described. Samples prepared on conventional total reflection X-ray fluorescence (TXRF) reflectors were measured at BESSY II synchrotron. A spatial resolution of 50 × 50 μm 2 was obtained, while the required time for the investigation of a 10 × 10 mm 2 sample is 30 seconds. The set-up is up to 350 times faster than conventional X-ray fluorescence systems for elemental traces. The major components of the X-ray camera are polycapillary optics and a pn-CCD chip with an active area of 13 × 13 mm 2. This area is divided into 264 × 264 pixels of 48 × 48 μm 2. A full X-ray spectrum with a resolution of 152 eV @ 5.9 keV and a chip temperature of 246 K is recorded for each pixel. The chip has a read-out rate of 400 Hz. © 2011 The Royal Society of Chemistry.


Patent
Pnsensor Gmbh and Pndetector Gmbh | Date: 2012-06-18

The invention relates to a semiconductor drift detector for detecting radiation, comprising a semiconductor substrate (HS), in which signal charge carriers are generated during operation, to be precise by incident photons (hf) having a specific photon energy, more particularly in the form of X-ray fluorescent radiation, and/or by incident electrons (), having a specific signal charge carrier current, more particularly in the form of back-scattered electrons (), and comprising a read-out anode (A) for generating an electrical output signal in a manner dependent on the signal charge carriers, and comprising an erase contact (RC) for erasing the signal charge carriers that have accumulated in the semiconductor substrate (HS). The invention provides for the semiconductor drift detector to be optionally operable in a first operating mode or in a second operating mode, wherein the semiconductor drift detector in the first operating mode measures the photon energy of the incident photons (hf), whereas the semiconductor drift detector in the second operating mode measures the signal charge carrier current. Furthermore, the invention encompasses a corresponding operating method.


Muller K.,University of Bremen | Ryll H.,PNSensor GmbH | Ordavo I.,PNSensor GmbH | Ihle S.,PNSensor GmbH | And 5 more authors.
Applied Physics Letters | Year: 2012

A high-speed direct electron detection system is introduced to the field of transmission electron microscopy and applied to strain measurements in semiconductor nanostructures. In particular, a focused electron probe with a diameter of 0.5 nm was scanned over a fourfold quantum layer stack with alternating compressive and tensile strain and diffracted discs have been recorded on a scintillator-free direct electron detector with a frame time of 1 ms. We show that the applied algorithms can accurately detect Bragg beam positions despite a significant point spread each 300 kV electron causes during detection on the scintillator-free camera. For millisecond exposures, we find that strain can be measured with a precision of 1.3 × 10 - 3, enabling, e.g., strain mapping in a 100 × 100 nm 2 region with 0.5 nm resolution in 40 s. © 2012 American Institute of Physics.


Send S.,University of Siegen | Abboud A.,University of Siegen | Hartmann R.,PNSensor GmbH | Huth M.,PNSensor GmbH | And 7 more authors.
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2013

In this work we study the response of a pnCCD by means of X-ray spectroscopy in the energy range between 6 keV and 20 keV and by Laue diffraction techniques. The analyses include measurements of characteristic detector parameters like energy resolution, count rate capability and effects of different gain settings. The limit of a single photon counting operation in white beam X-ray diffraction experiments is discussed with regard to the occurrence of pile-up events, for which the energy information about individual photons is lost. In case of monochromatic illumination the pnCCD can be used as a fast conventional CCD with a charge handling capacity (CHC) of about 300,000 electrons per pixel. If the CHC is exceeded, any surplus charge will spill to neighboring pixels perpendicular to the transfer direction due to electrostatic repulsion. The possibilities of increasing the number of storable electrons are investigated for different voltage settings by exposing a single pixel with X-rays generated by a microfocus X-ray source. The pixel binning mode is tested as an alternative approach that enables a pnCCD operation with significantly shorter readout times. © 2013 Elsevier B.V.

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