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Becker J.,University of Hamburg | Grtner K.,Weierstrass Institute for Applied Analysis And Stochastics | Klanner R.,University of Hamburg | Richter R.,Max Planck Institute Halbleiterlabor
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2010

In silicon sensors high densities of electron-hole pairs result in a change of the current pulse shape and spatial distribution of the collected charge compared to the situation in presence of low charge carrier densities. This paper presents a detailed comparison of numerical simulations with time resolved current measurements on planar silicon sensors using 660 nm laser light to create different densities of electron hole pairs. © 2010 Elsevier B.V. All rights reserved. Source


Gallrapp C.,CERN | La Rosa A.,CERN | MacChiolo A.,Max Planck Institute for Physics | Nisius R.,Max Planck Institute for Physics | And 3 more authors.
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2012

The performance of novel n-in-p planar pixel detectors designed for future upgrades of the ATLAS Pixel system is presented. The n-in-p silicon sensors technology is a promising candidate for the pixel upgrade thanks to its radiation hardness and cost effectiveness that allow for enlarging the area instrumented with pixel detectors. The n-in-p modules presented here are composed of pixel sensors produced by CiS connected by bump-bonding to the ATLAS read-out chip FE-I3. The characterization of these devices has been performed before and after irradiation up to a fluence of 5×10 15 1 MeV n eqcm -2. Charge collection measurements carried out with radioactive sources have proven the functioning of this technology up to these particle fluences. First results from beam test data with a 120 GeV/c pion beam at the CERN-SPS are also discussed, demonstrating a high tracking efficiency of (98.6±0.3)% and a high collected charge of about 10 ke for a device irradiated at the maximum fluence and biased at 1 kV. © 2012 Elsevier B.V. All rights reserved. Source


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. Source


Scharf O.,BAM Federal Institute of Materials Research and Testing | Ihle S.,PNSensor GmbH | Ordavo I.,PNDetector GmbH | Arkadiev V.,Institute fur Angewandte Photonik E.V. IAP | And 18 more authors.
Analytical Chemistry | Year: 2011

For many applications there is a requirement for nondestructive analytical investigation of the elemental distribution in a sample. With the improvement of X-ray optics and spectroscopic X-ray imagers, full field X-ray fluorescence (FF-XRF) methods are feasible. A new device for high-resolution X-ray imaging, an energy and spatial resolving X-ray camera, is presented. The basic idea behind this so-called "color X-ray camera" (CXC) is to combine an energy dispersive array detector for X-rays, in this case a pnCCD, with polycapillary optics. Imaging is achieved using multiframe recording of the energy and the point of impact of single photons. The camera was tested using a laboratory 30 μm microfocus X-ray tube and synchrotron radiation from BESSY II at the BAMline facility. These experiments demonstrate the suitability of the camera for X-ray fluorescence analytics. The camera simultaneously records 69 696 spectra with an energy resolution of 152 eV for manganese K α with a spatial resolution of 50 μm over an imaging area of 12.7 × 12.7 mm2. It is sensitive to photons in the energy region between 3 and 40 keV, limited by a 50 μm beryllium window, and the sensitive thickness of 450 μm of the chip. Online preview of the sample is possible as the software updates the sums of the counts for certain energy channel ranges during the measurement and displays 2-D false-color maps as well as spectra of selected regions. The complete data cube of 264 × 264 spectra is saved for further qualitative and quantitative processing. © 2011 American Chemical Society. Source


Ekeberg T.,Uppsala University | Svenda M.,Uppsala University | Abergel C.,Aix - Marseille University | Maia F.R.N.C.,Uppsala University | And 32 more authors.
Physical Review Letters | Year: 2015

We present a proof-of-concept three-dimensional reconstruction of the giant mimivirus particle from experimentally measured diffraction patterns from an x-ray free-electron laser. Three-dimensional imaging requires the assembly of many two-dimensional patterns into an internally consistent Fourier volume. Since each particle is randomly oriented when exposed to the x-ray pulse, relative orientations have to be retrieved from the diffraction data alone. We achieve this with a modified version of the expand, maximize and compress algorithm and validate our result using new methods. © 2015 American Physical Society. Source

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