1,720,970 research outputs found
Timing Performances of SDD as Photodetector Candidate for Proton Therapy Application
No full textIn proton therapy, charged particles interact with tissue depositing dose in the tumor, providing enhanced tumor coverage compared to conventional radiotherapy. However, proton range uncertainties limit the full exploitation in clinical practice of the localized dose deposition. Range and dose monitoring in real-time would be beneficial to deliver safer and more effective treatments. A possible solution is to use the signature of high-energy (2–8 MeV) prompt gamma rays, produced naturally along the beam path by excited nuclei. In this paper, we study the timing capability of the Silicon Drift Detector (SDD) as a photodetector candidate to be used for the scintillator readout for high-energy gamma rays detection. The peculiar drift mechanism affects the time needed for the photogenerated charge inside the SDD volume to approach the collecting electrode. As a result, the detector output signal shows a rise time limiting usually its timing performances when used with scintillators. In this work, we first developed a simulator to predict the drift time values as a function of charge generation position. Next, we performed the experimental characterization of the SDD timing performances by directly irradiating it with laser light. We carried out spectroscopy measurements for the assessment of the electronics noise of the detector in two readout configurations: single anode and merged anodes. Finally, we experimentally evaluated the timing performances of the SDD at the signal levels expected in the target application, showing sub-ns timing resolution
INTEGRATING LASER SCANNER AND BIM FOR CONSERVATION AND REUSE: “THE LYRIC THEATRE OF MILAN”
Full text linkThe paper underlines the importance to apply a methodology that integrates the Building Information Modeling (BIM), Work Breakdown Structure (WBS) and the Laser Scanner tool in conservation and reuse projects. As it is known, the laser scanner technology provides a survey of the building object which is more accurate rather than that carried out using traditional methodologies. Today most existing buildings present their attributes in a dispersed way, stored and collected in paper documents, in sheets of equipment information, in file folders of maintenance records. In some cases, it is difficult to find updated technical documentation and the research of reliable data can be a cost and time-consuming process. Therefore, this new survey technology, embedded with BIM systems represents a valid tool to obtain a coherent picture of the building state. The following case consists in the conservation and reuse project of Milan Lyric Theatre, started in 2013 from the collaboration between the Milan Polytechnic and the Municipality. This project first attempts to integrate these new techniques which are already professional standards in many other countries such as the US, Norway, Finland, England and so on. Concerning the methodology, the choice has been to use BIM software for the structured analysis of the project, with the aim to define a single code of communication to develop a coherent documentation according to rules in a consistent manner and in tight schedules. This process provides the definition of an effective and efficient operating method that can be applied to other projects
Innovative participatory evaluation processes: The case of the ministry of defense real-estate assets in Italy
No full textThe introduction of Public Deliberative Practices approach is not recent among all decision-making processes that are—directly or through associations representing collective interests—oriented to community involvement. Although the use of these practices is consensus-oriented, the pursuit of specific knowledge and choice democratization, involving communities and their territories together with man-made environments, become ever more important since it offers opportunities for discussions that designers, planners, promoters of processes are often reluctant to undertake. Now that Pope Francis claims that “A consensus should always be reached between the different stakeholders, who can offer a variety of approaches, solutions and alternatives”, the evolution of decision-making processes, forged over the past 10–20 years finds a new opportunity for legitimation. The theme of the Ministry of Defense’s actions concerning the disposal and development of the built heritage—widely debated during recent years—is likely to be one of the paradigms of transparency within the declined decision-making process, in particular, in relation to the Participatory Spaces Planning. The goals of the Ministry of Defense for the property sector are the rationalization and development of military infrastructures—in line with art. 26, DL 133/2014, so-called “Sblocca Italia”—through the optimization of the ones still needed and the allocation to other purposes of those not essential anymore. Once accepted, this scenario for urban and economic regeneration, aimed at increasing social welfare and quality of life, is necessary to establish a path for transformation, including participatory-planning processes starting from citizens’ involvement. The recent and quick progress of Information Construction Technology (ICT) Systems that facilitate a successful organization of information allows the optimization of the decisional process and the achievement of more readable and, if possible, more sharable results between public entities and private citizens
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
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
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
Charge Sensitive Amplifier with Offset-Compensated V-to-I Converter for the Mini-SDD-Based DSSC Detector
No full textIn this article, we present the study and the experimental results of a charge sensitive amplifier (CSA) for the mini-silicon drift detector (SDD) pixel sensors of the DEPleted Field-Effect Transistor (DEPFET) sensor with signal compression (DSSC) detector for photon science applications at the European X-ray free electron laser (XFEL) GmbH in Hamburg area. The DSSC detector must be able to cope with an image frame rate up to 4.5 MHz and with a dynamic range up to 104 photons/pixel/pulse for a photon energy of 1 keV. These goals will be pursued with the adoption of the DEPFET detector strategy. For the first camera prototype, a simpler solution based on a mini-SDD array read out by a conventional CSA has been adopted. We present here the CSA solution with a very simple V-to-I converter stage, which allows the self-canceling of the offset current flowing between the CSA and the filter, without the need of an intermediate stage. The CSA is compatible with the same application-specified integrated circuit (ASIC) architecture and readout chain already designed for the DEPFET detector. We present two versions of the CSA: one with a linear response and another with a nonlinear output characteristic. The nonlinear version provides increased input dynamic range preserving single-photon sensitivity. The experimental measurements have demonstrated the functionality of the proposed self-canceling solution and good noise performance with an equivalent noise charge (ENC) of 65 e- rms at the 4.5-MHz frame rate and a linearity error lower than 0.25% of the complete channel. In addition, the functionality of the nonlinear version (signal compression version) of the CSA has been demonstrated, without penalty in noise performance in the linear region of the CSA response
Assessment of Silicon Drift Detector Timing Performance for Proton Therapy Application
No full textProton therapy is a growing modality for cancer treatment, thanks to the finite penetration range of protons with a localized dose deposition maximum. However, range uncertainties prevent full exploitation of these advantages in clinical practice, leading to the need of range monitoring during treatment. One approach is to take advantage of high-energy (2 – 8 MeV) prompt-gamma (PG) rays, naturally produced in nuclear reactions between protons and target nuclei. In this paper, we study the timing performances of the Silicon Drift Detector (SDD) as a photodetector candidate to be used for the scintillator readout for high-energy gamma detection in this application. The peculiar drift mechanism of the charge created inside the SDD volume is responsible for a non-negligible rise time of the signal at the output of the device. In this work, the effect of the drift mechanism
on the timing performances of SDDs is first theoretically assessed in a device-level simulation. Next, experimental evaluation of the timing resolution is performed by directly irradiating the sensor with laser light
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