Performance of the diamond active target prototype for the PADME experiment at the DAΦ\PhiNE BTF

The PADME experiment at the DA$\Phi$NE Beam-Test Facility (BTF) is designed to search for the gauge boson of a new $\rm U(1)$ interaction in the process e$^+$e$^-\rightarrow\gamma$+$\rm A'$, using the intense positron beam hitting a light target. The $\rm A'$, usually referred as dark photon, is assumed to decay into invisible particles of a secluded sector and it can be observed by searching for an anomalous peak in the spectrum of the missing mass measured in events with a single photon in the final state. The measurement requires the determination of the 4-momentum of the recoil photon, performed by a homogeneous, highly segmented BGO crystals calorimeter. A significant improvement of the missing mass resolution is possible using an active target capable to determine the average position of the positron bunch with a resolution of less than 1 mm. This report presents the performance of a real size $\rm (2x2 cm^2)$ PADME active target made of a thin (50 $\mu$m) diamond sensor, with graphitic strips produced via laser irradiation on both sides. The measurements are based on data collected in a beam test at the BTF in November 2015.Comment: 7 pages, 10 figure

Semantic Web Technologies Meet BIM for Accessing and Understanding Cultural Heritage

Within the EU funded project INCEPTION – Inclusive Cultural Heritage in Europe through 3D semantic modelling, the key-targeted achievement is the development of a specific cloud based platform, in order to accomplish the main objectives of accessing, understanding and strengthening European Cultural Heritage by means of enriched 3D models. The whole INCEPTION project is based on the close connection between state-of-the-art architectural modeling technologies (BIM, Building Information Modeling) and the latest cutting-edge web technologies. The platform is grounded on semantic web technologies and makes extensive use of WebGL and RESTful APIs, in order to enrich heritage 3D models by using Semantic Web standards. The INCEPTION platform will be a space for interchange of information and for the dialogue among professionals, students, scholars, curators, non-expert users, etc. Furthermore, the Semantic Web structure interlinks the platform with external Cultural Heritage available linked data and makes it gradually enhanced by specific flexible data structures provided as project specific ontologies. The paper will describe solutions based on the match between BIM, Cloud and Semantic Web

Statistics of non-linear stochastic dynamical systems under L\'evy noises by a convolution quadrature approach

This paper describes a novel numerical approach to find the statistics of the non-stationary response of scalar non-linear systems excited by L\'evy white noises. The proposed numerical procedure relies on the introduction of an integral transform of Wiener-Hopf type into the equation governing the characteristic function. Once this equation is rewritten as partial integro-differential equation, it is then solved by applying the method of convolution quadrature originally proposed by Lubich, here extended to deal with this particular integral transform. The proposed approach is relevant for two reasons: 1) Statistics of systems with several different drift terms can be handled in an efficient way, independently from the kind of white noise; 2) The particular form of Wiener-Hopf integral transform and its numerical evaluation, both introduced in this study, are generalizations of fractional integro-differential operators of potential type and Gr\"unwald-Letnikov fractional derivatives, respectively.Comment: 20 pages, 5 figure

A tough egg to crack: recreational boats as vectors for invasive goby eggs and transdisciplinary management approaches

Non-native invasive species are a major threat to biodiversity, especially in freshwater ecosystems. Freshwater ecosystems are naturally rather isolated from one another. Nonetheless, invasive species often spread rapidly across water sheds. This spread is to a large extent realized by human activities that provide vectors. For example, recreational boats can carry invasive species propagules as ‘aquatic hitch-hikers’ within and across water sheds. We used invasive gobies in Switzerland as a case study to test the plausibility that recreational boats can serve as vectors for invasive fish and that fish eggs can serve as propagules. We found that the peak season of boat movements across Switzerland and the goby spawning season overlap temporally. It is thus plausible that goby eggs attached to boats, anchors or gear may be transported across watersheds. In experimental trials we found that goby eggs show resistance to physical removal (90mN attachment strength of individual eggs) and stay attached if exposed to rapid water flow (2.8m s-138 for 1h). When exposing the eggs to air, we found that hatching success remained high (>95%) even after eggs had been out of water for up to 24h. It is thus plausible that eggs survive during pick up, within water and overland transport by boats. We complemented the experimental plausibility tests with a survey on how decision makers from inside and outside academia rate the feasibility of managing recreational boats as vectors. We found consensus that an installation of a preventive boat vector management is considered an effective and urgent measure. This study advances our understanding of the potential of recreational boats to serve as vectors for invasive vertebrate species, and demonstrates that preventive management of recreational boats is considered feasible by relevant decision makers in- and outside academia

Low energy high angular resolution neutral atom detection by means of micro-shuttering techniques: the BepiColombo SERENA/ELENA sensor

The neutral sensor ELENA (Emitted Low-Energy Neutral Atoms) for the ESA cornerstone BepiColombo mission to Mercury (in the SERENA instrument package) is a new kind of low energetic neutral atoms instrument, mostly devoted to sputtering emission from planetary surfaces, from E ~20 eV up to E~5 keV, within 1-D (2x76 deg). ELENA is a Time-of-Flight (TOF) system, based on oscillating shutter (operated at frequencies up to a 100 kHz) and mechanical gratings: the incoming neutral particles directly impinge upon the entrance with a definite timing (START) and arrive to a STOP detector after a flight path. After a brief dissertation on the achievable scientific objectives, this paper describes the instrument, with the new design techniques approached for the neutral particles identification and the nano-techniques used for designing and manufacturing the nano-structure shuttering core of the ELENA sensor. The expected count-rates, based on the Hermean environment features, are shortly presented and discussed. Such design technologies could be fruitfully exported to different applications for planetary exploration.Comment: 11 page

INFN Camera demonstrator for the Cherenkov Telescope Array

The Cherenkov Telescope Array is a world-wide project for a new generation of ground-based Cherenkov telescopes of the Imaging class with the aim of exploring the highest energy region of the electromagnetic spectrum. With two planned arrays, one for each hemisphere, it will guarantee a good sky coverage in the energy range from a few tens of GeV to hundreds of TeV, with improved angular resolution and a sensitivity in the TeV energy region better by one order of magnitude than the currently operating arrays. In order to cover this wide energy range, three different telescope types are envisaged, with different mirror sizes and focal plane features. In particular, for the highest energies a possible design is a dual-mirror Schwarzschild-Couder optical scheme, with a compact focal plane. A silicon photomultiplier (SiPM) based camera is being proposed as a solution to match the dimensions of the pixel (angular size of ~ 0.17 degrees). INFN is developing a camera demonstrator made by 9 Photo Sensor Modules (PSMs, 64 pixels each, with total coverage 1/4 of the focal plane) equipped with FBK (Fondazione Bruno Kessler, Italy) Near UltraViolet High Fill factor SiPMs and Front-End Electronics (FEE) based on a Target 7 ASIC, a 16 channels fast sampler (up to 2GS/s) with deep buffer, self-trigger and on-demand digitization capabilities specifically developed for this purpose. The pixel dimensions of $6\times6$ mm$^2$ lead to a very compact design with challenging problems of thermal dissipation. A modular structure, made by copper frames hosting one PSM and the corresponding FEE, has been conceived, with a water cooling system to keep the required working temperature. The actual design, the adopted technical solutions and the achieved results for this demonstrator are presented and discussed.Comment: In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions at arXiv:1508.0589