1,720,964 research outputs found
CASPER-AI: a Machine Learning Method for Enhanced Active Collimation in Multichannel SDDs
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Preliminary Design of a Large Solid Angle X-ray Detector with Backscattering Geometry for High-Count-Rate Applications
No full textWe introduce an optimized geometry for an X-ray detector named ASCANIO: an innovative 16-channel SDD-based spectrometer purposefully crafted for X-ray fluorescence microscopy (XFM) imaging in synchrotron beamlines. This novel detector adopts a backscattering configuration with a tilted SDD arrangement, achieving a solid angle of 1 sr at a 8 mm sample distance with a potential Output Count Rate exceeding 20 Mcps. With a thickness of 1 mm, the SDD ensures a good absorption efficiency of 65% at 20 keV, all while maintaining an energy resolution of 150 eV at a peaking time of 100 ns thanks to a dedicated cooling system and low-noise front-end electronics
Optimization of Solid Angle and Count Rate Capability of an X-ray Detector with Backscattering Geometry
No full textVariations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
A 144-SiPM 3” LaBr3 readout module for PMTs replacement in Gamma spectroscopy
No full textA SiPM-based gamma-ray detection module for substituting bulky Photomultiplier Tubes in the readout of large scintillation crystals is presented. The system can be coupled to scintillators up to 3 inches in diameter, with state-of-the-art energy resolution (2.6% at 662 keV) and 80 keV - 20 MeV energy Dynamic Range, simultaneously achieved for the first time. Position sensitivity can also be achieved. Measurements show that a complete replacement of PMTs with SiPMs is already possible thanks to enhancements in silicon technology and lowering costs, making SiPMs a severe contender in many fields now dominated by vacuum-tubes technology
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Towards Real-Time Active Collimation in Monolithic Arrays of Silicon Drift Detectors
No full textWe propose a study of active collimation for multi-element monolithic Silicon Drift Detectors (SDDs) based on real-time recognition of charge sharing events, exploiting key parameters such as the rise time of voltage step signals at the output of the charge-sensitive preamplifier (CSA), and the occurrence in a specific coincidence window of events generated in adjacent pixels.This method aims to overcome common issues of widely-employed mechanical collimation, especially in small-pixel-size detectors where a large part of the active area is covered by the physical collimator which becomes, moreover, quite complex to be manufactured for small apertures.Firstly, we performed measurements with a pulsed laser system providing a 4 μm spot size beam scanning the SDD surface with 10 μm steps, thanks to a 3-axis manual translating stage, to ensure a precise assessment of the charge sharing region.Afterward, we measured events generated by a 55 Fe X-ray source at the CSA output on an uncollimated 16-channel monolithic detector to assess the algorithm's capability of rejecting events with partial charge collection while retaining as many non-charge sharing events as possible. This method paves the way also for the possibility of summing partial events on adjacent pixels in order to recover as useful signals those charge sharing photons that would otherwise be discarded, thus maintaining the advantages of mechanical collimation while maximizing the active area
Preliminary Design of a Large Solid Angle X-ray Detector with Backscattering Geometry for High-Count-Rate Applications
No full textWe introduce an optimized geometry for an X-ray detector named ASCANIO: an innovative 16-channel SDD-based spectrometer purposefully crafted for X-ray fluorescence microscopy (XFM) imaging in synchrotron beamlines. This novel detector adopts a backscattering configuration with a tilted SDD arrangement, achieving a solid angle of 1 sr at a 8 mm sample distance with a potential Output Count Rate exceeding 20 Mcps. With a thickness of 1 mm, the SDD ensures a good absorption efficiency of 65% at 20 keV, all while maintaining an energy resolution of 150 eV at a peaking time of 100 ns thanks to a dedicated cooling system and low-noise front-end electronics
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