212 research outputs found

    A New Fast Silicon Photomultiplier Photometer

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    The realization of low-cost instruments with high technical performance is a goal which deserves some efforts in an epoch of fast technological developments: indeed such instruments can be easily reproduced and therefore allow to open new research programs in several Observatories. We realized a fast optical photometer based on the SiPM technology, using commercially available modules. Using low-cost components we have developed a custom electronic chain to extract the signal produced by a commercial MPPC module produced by Hamamatsu, in order to obtain sub millisecond sampling of the light curve of astronomical sources, typically pulsars. In the early February 2011 we observed the Crab Pulsar at the Cassini telescope with our prototype photometer, deriving its period, power spectrum and shape of its light curve in very good agreement with the results obtained in the past with other instruments.Comment: Accepted for Publications of the Astronomical Society of Pacific (PASP), 8 pages, 8 figure

    SiFAP: A New Fast Astronomical Photometer

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    A fast photometer based on SiPM technology was developed and tested at the University of Rome "La Sapienza" and at the Bologna Observatory. In this paper we present the improvements applied to our instrument, concerning new cooled sensors, a new version of the electronics and an upgraded control timing software

    SiFAP: A New Fast Astronomical Photometer

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    A fast photometer based on SiPM technology was developed and tested at the University of Rome "La Sapienza" and at the Bologna Observatory. In this paper we present the improvements applied to our instrument, concerning new cooled sensors, a new version of the electronics and an upgraded control timing software

    Timing and modality of the sclerosing agents binding to the human proteins: laboratory analysis and clinical evidences

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    Sclerosing agents (SA) are blood inactivated. Nevertheless, investigations concerning the interaction among SA and blood components have never been deeply investigated. Aim of the study is to precisely identify SA blood ligands, to determine their binding time and to highlight the clinical consequences. Thirty-one blood samples were collected from chronic venous disease patients and tested by capillary and agarose gel (AGE) electrophoresis before and after adding polidocanol (POL) and sodiumtetradecylsulphate (STS). The two different types of electrophoresis allowed an evaluation of the blood proteins binding with the sclerosing agents, with a reaction time lower than 8 seconds for the AGE. Subsequently six patients underwent foam sclerotherapy and then were subdivided in group A (4 patients) and B (2 patients). In group A blood sample was obtained from the ipsilateral brachial vein immediately before (T0) and repeated 1, 3, 5, and 10 minutes after injection of STS 3% injection into the GSV. In group B, the same procedure was performed with the same timing from the ipsilateral femoral vein. Free STS (fSTS) and total proteinbound STS (bSTS) were measured. POL mainly binds to β-globulins (11%), while STS to albumin and α-globulins (62.6% and 30.7%) on the protidogram, respectively. Both in the brachial and in the femoral vein, the average fSTS was always 0. STS binds to albumin (62.6%) and α-globulins (30.7%), while POL is bound mainly by the b-globulins (11%). The present paper demonstrates how the vast majority of the sclerosing agent is bound to the blood proteins, suggesting the need to look for possible sclerotherapy complications factors also in the used gas and/or in the subsequent cathabolites release

    The MURAVES muon telescope: technology and expected performances

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    The MURAVES project aims to study the inner structure of the upper part of the Mt. Vesuvius volcano by muon radiography (muography) technique. Very high energy muons, produced by cosmic rays in the at- mosphere, can penetrate large thickness of rocks. By measuring the at- tenuation of the muons flux trough the volcano cone is possible to obtain a 2D image of the density structure. Internal discontinuities, with a spa- tial resolution of about 10 m, can be, in principle, resolved. An absolute average density measurement can be provided too. The project, funded by the Italian Ministry of University, Research and Education (MIUR), is led by INGV and INFN. In this article the mechanical structure of the de- tectors and background suppression techniques are reported

    The MURAVES telescope front-end electronics and data acquisition

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    The MURAVES detector is a 4 m 2 muon tracker equipped with a low power consumption electronic and designed to work in volcanic areas. Due to the great amount of channels (~1500) the detector is equipped with a multilayer electronic for data acquisition. It consists of 12 slave boards and 1 master board per square meter of detector and a single Raspberry Pi board that rules the whole set of one-square-meter detectors. Because of this modularity, we can enlarge in principle the detector surface by adding more one-square-meter elements. In the present work, we resume the main features of the MURAVES detector designed for the muography of volcanoes and, more generally, for the imaging of the underground. We focus on the capability to fine tune every single channel of the detector and the precise measure of the time of flight of the muons. The latter uses a time expansion technique and it should allow us to make a background rejection never obtained until now
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