1,721,393 research outputs found
Development of a single-photon imaging detector with pixelated anode and integrated digital read-out
No full textWe present the development of a single-photon detector and the connected
read-out electronics. This `hybrid' detector is based on a vacuum tube,
transmission photocathode, microchannel plate and a pixelated CMOS read-out
anode encapsulating the analog and digital-front end electronics. This assembly
will be capable of detecting up to photons per second with simultaneous
measurement of position and time.
The pixelated read-out anode used is based on the Timepix4 ASIC
( CMOS technology) designed in the framework of the Medipix4
collaboration. This ASIC is an array of pixels distributed on a
square pitch, with a sensitive area of . It features - equivalent noise charge,
a maximum rate of , and allows to time-stamp the
leading-edge time and to measure the Time-over-Threshold (ToT) for each pixel.
The pixel-cluster position combined with its ToT information will allow to
reach - position resolution. This information can also be
used to correct for the leading-edge time-walk achieving a timing resolution of
the order of .
The detector will be highly compact thanks to the encapsulated front-end
electronics allowing local data processing and digitization. An FPGA-based data
acquisition board, placed far from the detector, will receive the detector hits
using electro-optical links operated at . The data
acquisition board will decode the information and store the relevant data in a
server for offline analysis.
These performance will allow significant advances in particle physics, life
sciences, quantum optics or other emerging fields where the detection of single
photons with excellent timing and position resolutions are simultaneously
required.Comment: 5 pages, 1 figure, Proceedings of the 12th International Conference
on Position Sensitive Detectors, 12 - 17 September 2021, University of
Birmingham, Birmingham, U
Performance of the hadron calorimeter for fnal experiment E687
No full textA sampling gas hadron calorimeter with tower readout geometry has been constructed for a photoproduction experiment, E687, at Fermilab. This experiment has run in the Wide Band photon beam with photons of maximum energy of 450 GeV. The calorimeter consists of 28 120×82×1.75 in. Fe plates interspersed with planes of extruded aluminum proportional tubes. Capacitively induced signals on electrode pads with a cylindrical geometry are read out. The preamplifier and shaping electronics, constructed from surface mount devices, are mounted on the detector. The system has a dynamic range that spans the region from minimum ionizing particles (mip) to a few hundred mips. Calibrating the system response was done using muons, electronic test signals, and by recording the pulse height of an 55Fe source with a proportional counter. Results on the details of the performance of the calorimeter and its use as an online trigger are described
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Variations on the Author
Get PDF“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
"Il giorno del giudizio" di Salvatore Satta: la possibilità di un romanzo impossibile
No full textUdin
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
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Fermilab Physics Department TVC chip
Get PDFThe Electronics Group in the Physics Department at Fermilab has designed and has had produced 20 prototypes of a full custom four channel time to voltage converter using the ES2 direct write 2 {mu}m CMOS process. The actual implementation of the design was performed under contract by ASIC designs Inc. of Naperville, Illinois. Each channel has two hit capability and one level of input buffering: that is, up to four voltages representing time internals can be stored from each input for later ADC conversion. The chip produces an edited list of hits and presents the appropriate analog value on its output for each digital value on its hit address lines. The next hit address and analog voltage in the event is presented in response to an external strobe. One current sum proportional to the number of inputs hit for each input buffer is also provided. The chip has been designed to be used on a fastbus TDC card developed here, but it is our belief that it could be adapted to many TDC applications. 2 refs., 8 figs
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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