343 research outputs found

    SiPM: Characterizations, modelling and VLSI front-end dedicated development

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    In this work we describe the results of performance tests and measures of SiPM of several sizes (1×1, 3×3, 5×5) delivered from MEPHI. The SiPMs have been studied both in steady and pulsed stimuli. Aging and temperature behavior are also discussed. Another test has been performed in order to obtain an electrical model of the SiPM to be used in analog simulations. Finally, a design of a pilot chip with 0.35 μm technology implementing a front-end for SiPM aimed to TOF applications with adjustable thresholds and very high dynamical range is described

    The ALTCRISS project on board the International Space Station

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    The Altcriss project aims to perform a long term survey of the radiation environment on board the International Space Station. Measurements are being performed with active and passive devices in different locations and orientations of the Russian segment of the station. The goal is to perform a detailed evaluation of the differences in particle fluence and nuclear composition due to different shielding material and attitude of the station. The Sileye-3/Alteino detector is used to identify nuclei up to Iron in the energy range above 60 MeV/n. Several passive dosimeters (TLDs, CR39) are also placed in the same location of Sileye-3 detector. Polyethylene shielding is periodically interposed in front of the detectors to evaluate the effectiveness of shielding on the nuclear component of the cosmic radiation. The project was submitted to ESA in reply to the AO in the Life and Physical Science of 2004 and data taking began in December 2005. Dosimeters and data cards are rotated every six months: up to now three launches of dosimeters and data cards have been performed and have been returned with the end of expedition 12 and 13.Comment: Accepted for publication on Advances in Space Research http://dx.doi.org/10.1016/j.asr.2007.04.03

    Launch of the Space experiment PAMELA

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    PAMELA is a satellite borne experiment designed to study with great accuracy cosmic rays of galactic, solar, and trapped nature in a wide energy range protons: 80 MeV-700 GeV, electrons 50 MeV-400 GeV). Main objective is the study of the antimatter component: antiprotons (80 MeV-190 GeV), positrons (50 MeV-270 GeV) and search for antimatter with a precision of the order of 10^-8). The experiment, housed on board the Russian Resurs-DK1 satellite, was launched on June, 15, 2006 in a 350*600 km orbit with an inclination of 70 degrees. The detector is composed of a series of scintillator counters arranged at the extremities of a permanent magnet spectrometer to provide charge, Time-of-Flight and rigidity information. Lepton/hadron identification is performed by a Silicon-Tungsten calorimeter and a Neutron detector placed at the bottom of the device. An Anticounter system is used offline to reject false triggers coming from the satellite. In self-trigger mode the Calorimeter, the neutron detector and a shower tail catcher are capable of an independent measure of the lepton component up to 2 TeV. In this work we describe the experiment, its scientific objectives and the performance in the first months after launch.Comment: Accepted for publication on Advances in Space Researc

    Silicon calorimeter for cosmic antimatter search

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    Abstract The silicon sampling calorimeter presented is conceived as a fine grained imaging device to carry out studies of the anti-matter component in the primary cosmic radiation; it will be used in balloon payload program starting in 1993. The first sampling layer (48×48 cm2) of this silicon calorimeter has been completed and successfully tested. We report the first results form studies performed at the CERN PS t7 beam. The complete calorimeter contains 20 xy sampling layers (strip pitch 3.6 mm) interleaved with 19 showering material planes (tungsten 0.5 X0). This allows to picture the transverse distributions of the shower in both coordinates at each sampling. The outstanding imaging capabilities reflects in high particle identification power. Preliminary results from beam tests performed with antiprotons at 3.5 GeV on a tower prototype of the calorimeter are reported

    Efficacy of nivolumab in pre-treated non-small-cell lung cancer patients harbouring KRAS mutations

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    Background: The present study investigated the efficacy and safety of nivolumab in pre-treated patients with advanced NSCLC harbouring KRAS mutations. Methods: Clinical data and KRAS mutational status were analysed in patients treated with nivolumab within the Italian Expanded Access Program. Objective response rate, progression-free survival and overall survival were evaluated. Patients were monitored for adverse events using the National Cancer Institute Common Terminology Criteria for Adverse Events. Results: Among 530 patients evaluated for KRAS mutations, 206 (39%) were positive while 324 (61%) were KRAS wild-type mutations. KRAS status did not influence nivolumab efficacy in terms of ORR (20% vs 17%, P = 0.39) and DCR (47% vs 41%, P = 0.23). The median PFS and OS were 4 vs 3 months (P = 0.5) and 11.2 vs 10 months (P = 0.8) in the KRAS-positive vs the KRAS-negative group. The 3-months PFS rate was significantly higher in the KRAS-positive group as compared to the KRAS-negative group (53% vs 42%, P = 0.01). The percentage of any grade and grade 3–4 AEs were 45% vs 33% (P = 0.003) and 11% vs 6% (P = 0.03) in KRAS-positive and KRAS-negative groups, respectively. Conclusions: Nivolumab is an effective and safe treatment option for patients with previously treated, advanced non-squamous NSCLC regardless of KRAS mutations

    A silicon imaging calorimeter prototype for antimatter search in space: experimental results

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    Abstract This report presents the results obtained with a prototype silicon-tungsten (Si-W) electromagnetic calorimeter, conceived as a fine-grained imaging device to carry out studies of the antimatter component in primary cosmic radiation. The calorimeter prototype contains 20 x , y sampling layers interleaved with 19 showering material planes. One sensitive layer is obtained with two silicon strip detectors (Si-D) (60 × 60) mm 2 , each divided into 16 strips, 3.6 mm wide; the two detectors are assembled back to back with perpendicular strips. This allows the transverse distributions of the shower in both coordinates at each sampling (0.5 X 0 ) to be pictured. The basic characteristics of the design and the experimental results obtained on a test beam at the CERN proton synchrotron (PS) for electrons and pions are reported. The main results presented are the response of the calorimeter to the electron at various energies (1–7 GeV), and the transverse shower profiles at different calorimeter depths as well as the patterns of the electromagnetic shower and those of the interacting and non-interacting pions. The capability of the calorimeter in measuring the direction of the incoming electromagnetic particle from the pattern of the shower has been evaluated at different energies. These results are encouraging in view of the possible use of this detector to search for high-energy γ sources in space
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