Investigation of a 2-Colour Undulator FEL Using Puffin

Initial studies of a 2-colour FEL amplifier using one monoenergetic electron beam are presented. The interaction is modelled using the unaveraged, broadband FEL code Puffin. A series of undulator modules are tuned to generate two resonant frequencies along the FEL interaction and a self-consistent 2-colour FEL interaction at widely spaced non-harmonic wavelengths at 1nm and 2.4nm is demonstrated.Comment: Submitted to The 35th International Free-Electron Laser Conference, Manhattan, New York (2013

Development of Prototype Pixellated PIN CdZnTe Detectors

We report initial results from the design and evaluation of two pixellated PIN Cadmium Zinc Telluride detectors and an ASIC-based readout system. The prototype imaging PIN detectors consist of 4X4 1.5 mm square indium anode contacts with 0.2 mm spacing and a solid cathode plane on 10X10 mm CdZnTe substrates of thickness 2 mm and 5 mm. The detector readout system, based on low noise preamplifier ASICs, allows for parallel readout of all channels upon cathode trigger. This prototype is under development for use in future astrophysical hard X-ray imagers with 10-600 keV energy response. Measurements of the detector uniformity, spatial resolution, and spectral resolution will be discussed and compared with a similar pixellated MSM detector. Finally, a prototype design for a large imaging array is outlined.Comment: 10 pages Latex, 9 figures, to appear in Proc. of SPIE Vol. 3446 "Hard X-ray and Gamma-Ray Detector Physics and Applications

Big Data Analytics on combining RADAR and optical remote sensing imagery

Remote sensing data is big, which makes it inherently not FAIR, due to the great burden put on the users, for the data to be truly Accessible. In turn, this makes it unfeasible to process data to an Interoperable form. The ESA’s Copernicus program raised the bar for quality data in earth observation satellite sensors ..

Medicinalpolizeiliches Einschreiten gegen marktschreierische Annoncen in Hamburg

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The declining share of primary data and the neglect of the individual level in international business research

Complementing Nielsen and colleagues’ (2020) analysis of methodological trends in the Journal of International Business Studies over the past 50 years, we examine similar data on methods published in a wider range of leading international business (IB) journals. Our analysis shows a clear decline of studies based on primary data relative to secondary data, and a persistently low level of individual-level studies among the growing body of research using secondary data across all IB journals considered. We discuss the main mechanisms driving these trends and identify the problems of IB’s increasing exposure to the risks inherent in secondary data. We also discuss the implications related to neglecting individual-level data for theory advancement in IB, such as a disregard for novel secondary data opportunities at the individual level and the risk of reduced theoretical pluralism. In doing so, we substantially extend the debate initiated by Nielsen and colleagues (2020)

Transportable setup for amplifier phase fidelity measurements

One possible laser source for the Laser Interferometer Space Antenna (LISA) consists of an Ytterbium-doped fiber amplifier originally developed for inter-satellite communication, seeded by the laser used for the technology demonstrator mission LISA Pathfinder. LISA needs to transmit clock information between its three spacecraft to correct for phase noise between the clocks on the individual spacecraft. For this purpose phase modulation sidebands at GHz frequencies will be imprinted on the laser beams between spacecraft. Differential phase noise between the carrier and a sideband introduced within the optical chain must be very low. We report on a transportable setup to measure the phase fidelity of optical amplifiers.DFG/EXC/QUESTDLR/50OQ1301DLR/50OQ060

Transport through open quantum dots: making semiclassics quantitative

We investigate electron transport through clean open quantum dots (quantum billiards). We present a semiclassical theory that allows to accurately reproduce quantum transport calculations. Quantitative agreement is reached for individual energy and magnetic field dependent elements of the scattering matrix. Two key ingredients are essential: (i) inclusion of pseudo-paths which have the topology of linked classical paths resulting from diffraction in addition to classical paths and (ii) a high-level approximation to diffractive scattering. Within this framework of the pseudo-path semiclassical approximation (PSCA), typical shortcomings of semiclassical theories such as violation of the anti-correlation between reflection and transmission and the overestimation of conductance fluctuations are overcome. Beyond its predictive capabilities the PSCA provides deeper insights into the quantum-to-classical crossover.Comment: 20 pages, 19 figure

Concepts and processing techniques for a global Sentinel 1-3 Land Cover Dynamics and Change (LCDC) product

The present study proposes a concept and a joint processing chain for integrating the ESA’s upcoming Sentinel 1-3 satellites to address the needs from a series of users. The framework considers the advantages of the single Sentinel systems in terms of the spatial, temporal and thematic detail for the generation of a global land cover dynamics and change (LCDC) product. In addition, a calibration and validation plan is discussed and open science issues to fully implement the product have been identified. In order to (i) address key user requirements and (ii) develop concepts and processing techniques for a global LCDC product that go beyond the current state-of-the-art, user requirements and available global state-of-the-art land cover efforts and retrieval approaches of similar nature and their shortcomings were considered

Simulation studies for dielectric wakefield programme at CLARA facility

Short, high charge electron bunches can drive high magnitude electric fields in dielectric lined structures. The interaction of the electron bunch with this field has several applications including high gradient dielectric wakefield acceleration (DWA) and passive beam manipulation. The simulations presented provide a prelude to the commencement of an experimental DWA programme at the CLARA accelerator at Daresbury Laboratory. The key goals of this program are: tunable generation of THz radiation, understanding of the impact of transverse wakes, and design of a dechirper for the CLARA FEL. Computations of longitudinal and transverse phase space evolution were made with Impact-T and VSim to support both of these goals.Comment: 10 Pages, 4 Figures, Proceedings of EAAC2017 Conferenc