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

Blue and green upconversion in Er(3+)-doped fluoroindate glasses

The upconversion properties of Er3+ in fluoroindate bulk glasses (composition: 40InF3-20ZnF2-16BaF2-(20-x)SrF2-2GaF3-2NaF-xErF3 with x=1,2,3 and 4 mole %) are investigated, following F-4(9/2) excitation with a red krypton laser. A strong green and a weaker blue luminescence is observed at room temperature corresponding to emissions from the thermally coupled S-4(3/2) and H-2(11/2) bands and the H-2(9/2) level respectively. Resonant energy transfer processes involving two excited erbium ions and a two-step absorption process are proposed to explain the upconversion phenomena. The emission intensities depend on the excitation power as P(exc)n with 1.5 less-than-or-equal-to n less-than-or-equal-to 1.7 for the green and 1.6 less-than-or-equal-to n less-than-or-equal-to 1.9 for the blue emission. The decay times and the relative intensities of the luminescences are also studied as a function of Er3+ concentration

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)

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

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

Rectangular Beads from the Final Gravettian Level of the Abri Pataud: Raw Material Identification and its Archaeological Implications

The Final Gravettian level (level 2) of the abri Pataud (Dordogne, France) yielded a large assemblage of body ornaments that consists essentially of 85 quite standardized rectangular beads. Some uncertainty remained about the raw material in which these small beads were made: mammoth ivory, reindeer antler or bone? Non-invasive methods were employed in order to determine the raw material. First chemical analyses using microbeam Proton Induced X-ray Emission analysis (microPIXE) did not enable us to conclude definitively. Therefore, synchrotron and laboratory X-ray microtomography (microCT) were applied on eight beads and allowed us to identify ivory for all of them except for one, which shows slightly different morphological features.Le niveau 2 (Gravettien final) de l’abri Pataud (Dordogne, France) a livré un nombre important d’éléments de parure. L’essentiel (n : 85) correspond à des perles rectangulaires assez standardisées. Certaines incertitudes demeuraient sur leur matière première : ivoire de mammouth, bois de renne ou os ? Des méthodes non-invasives ont alors été employées pour déterminer la nature précise de celles-ci. Les analyses élémentaires par spectrométrie d’émission X induite par particules (PIXE) n’ayant pas été concluantes, la microtomographie de rayons X en laboratoire et au synchrotron a été utilisée sur huit perles et a permis d’identifier le matériau comme étant de l’ivoire, excepté pour l’une d’entre elles qui présente quelques légères différences de structure

INVESTIGATION OF A 2-COLOUR UNDULATOR FEL USING PUFFIN

Abstract 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

Employing electro-mechanical analogies for co-resonantly coupled cantilever sensors

Understanding the behaviour of mechanical systems can be facilitated and improved by employing electro-mechanical analogies. These analogies enable the use of network analysis tools as well as purely analytical treatment of the mechanical system translated into an electric circuit. Recently, we developed a novel kind of sensor set-up based on two coupled cantilever beams with matched resonance frequencies (co-resonant coupling) and possible applications in magnetic force microscopy and cantilever magnetometry. In order to analyse the sensor's behaviour in detail, we describe it as an electric circuit model. Starting from a simplified coupled harmonic oscillator model with neglected damping, we gradually increase the complexity of the system by adding damping and interaction elements. For each stage, various features of the coupled system are discussed and compared to measured data obtained with a co-resonant sensor. Furthermore, we show that the circuit model can be used to derive sensor parameters which are essential for the evaluation of measured data. Finally, the much more complex circuit representation of a bending beam is discussed, revealing that the simplified circuit model of a coupled harmonic oscillator is a very good representation of the sensor system