First results of the two square meters multilayer glass composite mirror design proposed for the Cherenkov Telescope Array developed at INFN

The Cherenkov Telescope Array (CTA) is a future ground-based gamma-ray astronomy detector that will consist of more than 100 Imaging Atmospheric Cherenkov Telescopes of different sizes. The total reflective surface of roughly 10 000 m$^2$ requires unprecedented technological efforts towards a cost-efficient production of light-weight and reliable mirror substrates at high production rate. We report on a new mirror concept proposed for CTA developed by INFN, which is based on the replication from a spherical convex mold under low pressure. The mirror substrate is an open structure design made by thin glass layers at the mirror's front and rear interspaced by steel cylinders. A first series of nominal size mirrors has been produced, for which we discuss the optical properties in terms of radius of curvature and focusing power

Geometrical Calibration for the Panrover: a Stereo Omnidirectional System for Planetary Rover

Abstract. A novel panoramic stereo imaging system is proposed in this paper. The system is able to carry out a 360° stereoscopic vision, useful for rover autonomous-driving, and capture simultaneously a high-resolution stereo scene. The core of the concept is a novel "bifocal panoramic lens" (BPL) based on hyper hemispheric model (Pernechele et al. 2016). This BPL is able to record a panoramic field of view (FoV) and, simultaneously, an area (belonging to the panoramic FoV) with a given degree of magnification by using a unique image sensor. This strategy makes possible to avoid rotational mechanisms. Using two BPLs settled in a vertical baseline (system called PANROVER) allows the monitoring of the surrounding environment in stereoscopic (3D) mode and, simultaneously, capturing an high-resolution stereoscopic images to analyse scientific cases, making it a new paradigm in the planetary rovers framework.Differently from the majority of the Mars systems which are based on rotational mechanisms for the acquisition of the panoramic images (mosaicked on ground), the PANROVER does not contain any moving components and can rescue a hi-rate stereo images of the context panorama.Scope of this work is the geometric calibration of the panoramic acquisition system by the omnidirectional calibration methods (Scaramuzza et al. 2006) based on Zhang calibration grid. The procedures are applied in order to obtain well rectified synchronized stereo images to be available for 3D reconstruction. We applied a Zhang chess boards based approach even during STC/SIMBIO-SYS stereo camera calibration (Simioni et al. 2014, 2017). In this case the target of the calibration will be the stereo heads (the BPLs) of the PANROVER with the scope of extracting the intrinsic parameters of the optical systems. Differently by previous pipelines, using the same data bench the estimate of the extrinsic parameters is performed

Video-based biomechanical analysis of an unexpected Achilles tendon rupture in an Olympic sprinter

We used image-processing techniques to determine the moment (i.e., image frame) of the Achilles tendon (AT) rupture in an Olympic sprinter. This report may be unique due to the difficulty in conducting motion capture analyses during injury events. Our report includes one female Olympic sprinter, 29 years old (body mass: 56 kg, height: 1.68 m, and body mass index: 19.8 kg/m2) with a high-competitive profile history (2008 and 2012 Olympic Games participation; South American record holder in 100- and 200-m; Pan-American gold medalist in 200-m and 4 x 100-m relay) who suffered a complete AT rupture in the left leg while exercising in the final phase of rehabilitation following an Achilles tendinopathy in the contralateral limb. The greater dorsiflexion found at the moment of the injury and the delayed control of heel position indicated the presence of uncontrolled dorsiflexion, which potentially generated excessive eccentric stress over the tendon and, thus, the AT rupture. Here we discuss the relevance of lower leg alignment, the movements’ characteristics, and the history of Achilles tendinopathy in the contralateral leg on the occurrence of the AT rupture

(Very) Fast astronomical photometry for meter-class telescopes

Our team at the INAF-Astronomical Observatory of Padova and the University of Padova is engaged in the design, construction and operations of instruments with very high time accuracy in the optical band for applications to High Time Resolution Astrophysics and Quantum Astronomy. Two instruments were built to perform photon counting with sub-nanosecond temporal accuracy, Aqueye+ and Iqueye. Aqueye+ is regularly mounted at the 1.8m Copernicus telescope in Asiago, while Iqueye was mounted at several 4m class telescopes around the world and is now attached through the Iqueye Fiber Interface to the 1.2m Galileo telescope in Asiago. They are used to perform coordinated high time resolution optical observations and, for the first time ever, experiments of optical intensity interferometry on a baseline of a few kilometers. We report on recent technological developments and scientific results obtained within the framework of this project...

Design of a SiPM-based cluster for the Large Size Telescope camera of CTA

A Silicon Photomultiplier (SiPM)-based photodetector is being built to demonstrate its feasibility for an alternative silicon-based camera design for the Large Size Telescope (LST) of the Cherenkov Telescope Array. It has been designed to match the size of the standard Photomultiplier Tube (PMT) cluster unit and to be compatible with mechanics, electronics and focal plane optics of the first LST camera. Here, we describe the overall SiPM cluster design along with the main differences with respect to the currently used PMT cluster unit. The fast electronics of the SiPM pixel and its layout are also presented. In order to derive the best working condition for the final unit, we measured the SiPM performances in terms of gain, photo-detection efficiency and cross-talk. One pixel, a unit of 14 SiPMs, has been built. We will discuss also some preliminary results regarding this device and we will highlight the future steps of this project.Comment: submitted to NIM

role of winter host plants in vineyard colonization and phenology of zygina rhamni hemiptera cicadellidae typhlocybinae

Abstract Zygina rhamni Ferrari (Hemiptera: Cicadellidae: Typhlocybinae) is a mesophyll-feeding leafhopper that infests grapevine, Vitis vinifera L. This leafhopper's overwintering strategy and the dynamics of its vineyard colonization, relative to the distance between the grapevines and the winter host plants and different grapevine vegetative densities, are described herein. This species shows a facultative heteroecious life cycle. In autumn, it migrates from vineyards to bramble, Rubus gr. fruticosus, and rose, Rosa chinensis Jacquin. On these host plants, females lay eggs that start to hatch at the end of March. Adults that developed on bramble colonize grapevines beginning in May; the leaf fall of rose, which takes place during the first half of April, probably causes the death of unhatched eggs and nymphs. We found that overwintering females can move back to vineyards and lay eggs until early June. The dynamics of vineyard colonization by the leafhopper involved initial concentration in areas close t..