1,720,993 research outputs found
Towards minimum material trackers for high energy physics experiments at upgraded luminosities
No full textReducing material in silicon trackers is of major importance for a good detector performance overall, and poses a big challenge in the development of the detectors. To match the low material desirable for trackers in High Energy Physics experiments at upgraded luminosities, special techniques have to be developed to address the main sources of material, i.e. mechanical structure and services, and to prevent new significant contributions to the detector material coming for instance from larger Front-End chips. In this framework three methods are developed to reduce the material added by services and electronics: (1)serial powering, (2) light weight aluminum flex cables and Through Silicon Vias, and (3) thin Front-End chips. The methods are presented in this paper using the upgrades of the ATLAS pixel detector as an example of application. (C) 2010 Elsevier B.V. All rights reserved
The shunt-LDO regulator to power the upgraded ATLAS pixel detector
No full textThe shunt-LDO regulator is a new regulator concept which combines a shunt and a Low Drop-Out (LDO) regulator. Designed as an improved shunt regulator to match the needs of serially powered detector systems, it can also be used as a pure LDO regulator for general application in powering schemes requiring linear regulation. The flexibility of the design makes the shunt-LDO regulator a good candidate for use in the powering schemes envisaged for the upgrades of the ATLAS pixel detector. Two shunt-LDO regulators integrated in the prototype of the next ATLAS pixel front-end chip, the FE-I4A, are used to demonstrate the feasibility of the proposed powering solutions
Performance evaluation of a serially powered pixel detector prototype for the HL-LHC
No full textEfficient and low mass power distribution presents a challenge for vertex and tracking detectors at the HL-LHC. Different approaches have been considered to transmit power at low current and high voltage. This paper presents the serial powering scheme proposed as baseline for the ATLAS and CMS pixel detectors at the HL-LHC. A serially powered detector prototype with six pixel modules has been built, featuring all elements needed for current distribution, redundancy, data transmission, and sensor biasing. Results of the characterisation of the prototype in standard operating conditions as well as in more challenging scenarios including increased digital activity are presented
A serial powering pixel stave prototype for the ATLAS ITk upgrade
No full textOne of the main challenges for the ATLAS ITk Phase II Pixel upgrade is low-mass efficient power distribution for detector modules. This requires a powering scheme alternative to the parallel (direct) powering which is currently used. A serial powering scheme has been chosen as the baseline for the ITk pixel system. A serially powered pixel detector prototype has been built with all the components that are needed for current distribution, data transmission, bypassing and redundancy in order to prove the feasibility of implementing serial powering scheme in the ITk. Detailed investigations of the electrical performance of the detector prototype equipped with FE-I4 quad modules have been made with the help of the USBpix3 readout system that has been developed in Bonn
A via last TSV process applied to ATLAS pixel detector modules: proof of principle demonstration
No full textVia last Through Silicon Vias (TSVs) can be exploited to build low material modules for the upgrades of the ATLAS pixel detector at the High Luminosity LHC. To prove this concept a via last TSV process is demonstrated on ATLAS pixel readout wafers. Demonstrator modules featuring 90 mu m thin readout chips with TSVs are operated using the connection from the back side of the chip. This paper illustrates the via formation process and the results from the characterization of modules with TSVs
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
A serial powering scheme for the ATLAS pixel detector at sLHC
No full textPowering concepts, such as serial powering and DC-DC conversion, are in development for the silicon trackers at sLHC to achieve an efficient power distribution with a minimum volume of cables. This paper will describe the serial powering scheme developed for the upgraded ATLAS pixel detector, with focus on the scheme architecture and on the main components involved: the Shunt-LDO regulator and the protection scheme. Issues connected to system aspects will be discussed, and the advantages in terms of material reduction provided by the proposed serial powering scheme will be presented
Variations 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
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
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