1,721,058 research outputs found
Theoretical comparison between two different filtering techniques suitable for the VLSI spectroscopic amplifier ROTOR
No full textThe development of new detection systems based on arrays of Silicon Drift Detectors (SDD) used for new X-ray spectroscopy applications, like X-ray Holography and EXAFS experiments, requires the realization of suitable integrated low-noise electronics for the readout of the detector signals. Recently, a new VLSI time-variant signal processor called ROTOR has been developed. Despite its time-variant nature ROTOR is capable of correctly processing events randomly distributed along the time axis, thanks to the employment of the Concurrent Wheel Technique (CWT). Two different possible solutions for the ROTOR chip have been developed, both suitable for the CWT working mechanism. A theoretical comparison between the noise performances of the two filtering methods has been carried out and is presented in this work. © 2003 Elsevier B.V. All rights reserved
The DEPFET sensor-amplifier structure: A method to beat 1/f noise and reach sub-electron noise in pixel detectors
No full textDepleted field effect transistors (DEPFET) are used to achieve very low noise signal charge readout with sub-electron measurement precision. This is accomplished by repeatedly reading an identical charge, thereby suppressing not only the white serial noise but also the usually constant 1/f noise. The repetitive non-destructive readout (RNDR) DEPFET is an ideal central element for an active pixel sensor (APS) pixel. The theory has been derived thoroughly and results have been verified on RNDR-DEPFET prototypes. A charge measurement precision of 0.18 electrons has been achieved. The device is well-suited for spectroscopic X-ray imaging and for optical photon counting in pixel sensors, even at high photon numbers in the same cell
Novel p-JFET embedded in silicon radiation detectors that avoids preamplifier feedback resistor
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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
VELA: The CMOS circuit based on fast current read-out for X-ray Spectroscopy with DePMOS
No full textDePMOS based Active Pixel Sensor (APS) matrix is a new detector concept for X-ray imaging spectroscopy applications. This type of X-ray detectors can provide excellent energy resolution and high-speed readout. Both these features and the advantage of random pixel accessibility can fulfill the requirements of new space missions, like the XEUS Wide Field Imager. In a matrix arrangement, each pixel must be read out by a time variant filter, so a new readout mechanism and a proper multi-channel integrated shaping amplifier are needed. Finally, to operate at such a reduced processing time (e.g. 4 mus per line) DePMOS transistor can not be operated in the classical source follower configuration, because this results in a long settling time; so challenging design of full-custom multi-channel readout electronic has to be considered. We propose a new faster readout concept, which is based on the drain current readout
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
Assessment of the Non-Linear Response of DEPFET Sensors with Signal Compression
No full textThe implementation of a Depleted Field Effect Transistor (DEPFET) in each pixel of the DSSC (DEPFET Sensor with Signal Compression) X-ray camera for the European XFEL is intended to provide the appropriate signal compression at high injection levels and low noise figure. The aim of this work is the assessment of the non-linear DEPFET response. To this purpose the response of DSSC DEPFET pixels has been measured and analyzed up to 2 MeV equivalent deposited energy in the experimental conditions foreseen for the final DSSC camera. An appropriate fitting function has been introduced to predict the compression “kink” positions and to model the shape of the compression curve. The preliminary results of this study will be summarized
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