1,077 research outputs found

    Transmission curves and effective refraction indices of MKO near infrared consortium filters at cryogenic temperatures

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    We report transmission measurements at cryogenic temperatures for 4 broad-band filters of the Mauna Kea Observatories (MKO) near-infrared filter set and 5 narrow-band filters. The spectral scans were collected using the multi-mode IR instrument of the TNG telescope (NICS) in which these filters are permanently mounted and commonly used for astronomical observations. We determined the transmission curves at a temperature of 78K and found no significant red-leak up to 2.6 microns, the data are available in electronic form on the TNG web page. We also estimated the variation of the wavelength response with the incidence angle and found it compatible with an effective refractive index of about 2

    The TNG Near Infrared Camera Spectrometer

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    NICS (acronym for Near Infrared Camera Spectrometer) is the near-infrared cooled camera-spectrometer that has been developed by the Arcetri Infrared Group at the Arcetri Astrophysical Observatory, in collaboration with the CAISMI-CNR for the TNG (the Italian National Telescope Galileo at La Palma, Canary Islands, Spain). As NICS is in its scientific commissioning phase, we report its observing capabilities in the near-infrared bands at the TNG, along with the measured performance and the limiting magnitudes. We also describe some technical details of the project, such as cryogenics, mechanics, and the system which executes data acquisition and control, along with the related software.Comment: 7 pages, 5 figures, compiled with A&A macros. A&A in pres

    A 5 Gb/s Radiation Tolerant Laser Driver

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    A laser driver for data transmission at 5 Gb/s has been developed as a part of the Giga Bit Transceiver (GBT) project. The Giga Bit Laser Driver (GBLD) targets High Energy Physics (HEP) applications for which radiation tolerance is mandatory. The GBLD ASIC can drive both VCSELs and some types of edge emitting lasers. It is essentially composed of two drivers capable of sinking up to 12 mA each from the load at a maximum data rate of 5 Gb/s, and of a current sink for the laser bias current. The laser driver include also pre-emphasis and duty cycle control capabilities

    Silicon Mie Resonators for Highly Directional Light Emission from monolayer MoS2

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    Controlling light emission from quantum emitters has important applications ranging from solid-state lighting and displays to nanoscale single-photon sources. Optical antennas have emerged as promising tools to achieve such control right at the location of the emitter, without the need for bulky, external optics. Semiconductor nanoantennas are particularly practical for this purpose because simple geometries, such as wires and spheres, support multiple, degenerate optical resonances. Here, we start by modifying Mie scattering theory developed for plane wave illumination to describe scattering of dipole emission. We then use this theory and experiments to demonstrate several pathways to achieve control over the directionality, polarization state, and spectral emission that rely on a coherent coupling of an emitting dipole to optical resonances of a Si nanowire. A forward-to-backward ratio of 20 was demonstrated for the electric dipole emission at 680 nm from a monolayer MoS2 by optically coupling it to a Si nanowire

    Performance of the CMS Cathode Strip Chambers with Cosmic Rays

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    The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

    Performance and Operation of the CMS Electromagnetic Calorimeter

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    The operation and general performance of the CMS electromagnetic calorimeter using cosmic-ray muons are described. These muons were recorded after the closure of the CMS detector in late 2008. The calorimeter is made of lead tungstate crystals and the overall status of the 75848 channels corresponding to the barrel and endcap detectors is reported. The stability of crucial operational parameters, such as high voltage, temperature and electronic noise, is summarised and the performance of the light monitoring system is presented

    3-d visualization and animation of architectonic elements for prehistoric megalithic temples of the island of Gozo: the temple of Ggantija

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    Laser scanning can now be defined without doubt as the newest frontier in the field of survey technique, and recent technological developments of instruments and processing software have encouraged the introduction of this technique in the world of applications connected to archaeological site and other related disciplines. The temple of Ggantija on the island of Gozo was considered to be representative of the entire series of temple complexes due to their particular architectural characteristics, their stage of evolution and form of deterioration, both material and structural. The survey was conducted by the use of the local geodetic network in the different phases: • Topographic survey • 3D laser scanner survey • Photographic Survey: both traditional and digital pictures will be taken in order to fully documentation internal and external surfaces of the site. The treatment and analysis of data collections was divided into the following sub-stages: elaboration and compensation of close polygonal, thickening polygonal and direct measurements; elaboration and compensation of altimetric network; linking of the above data with the existing Maltese national networks; elaboration of laser scanner positions and absolute orientations; elaboration of points coordinates for georeferencing and linking the point clouds coming from laser; final data verification end quality control; analysis of laser measured point clouds, for filtering and subsequent elaboration; scanning orientations and subdivision into “islands” (internal rooms and external sides); analysis of laser measured point clouds over the grid determined by the topographic survey.; modelling of the Archaeological site, elimination of noises and metric "pollution" by statistics and verification; accentuation and reduction of triangles on areas interested by complex geometries; triangles transformation into complex surfaces (mesh); model checking by topographic points; mapping of digital photocolors covering all the surfaces of the site. The digital model will be cut by vertical and horizontal section plans at heights requested by customer 2D graphic editing of the plans, sections and elevations. Finishing of vertical sections (sections and views) using the mapped model created by rendering calculated, generating contours lines from the 3D model; of a light model (low density model) of the laser scanner data using the filtering tools of the software package; of an virtual animation of the high density model; of a mapped VRML (Virtual Reality Modelling Language) model for a web interactive and hypertestual navigation, using the low density model. This part of the study was aimed at defining the architectural characteristics and mode of construction of this monument

    Внедрение и принцип работы системы сейсмического мониторинга горного массива для работы в условиях ООО "Шахта "Усковская"

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    The status of the Silicon Microvertex Detector (SMD) and its installation into the LEP-L3 experiment are presented, highlighting novel features and sophisticated techniques. Preliminary results based on 1993 data are given and compared with Monte Carlo predictions, to understand the detector performances and its tracking capabilities

    Test beam performance measurements for the Phase I upgrade of the CMS pixel detector

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    A new pixel detector for the CMS experiment was built in order to cope with the instantaneous luminosities anticipated for the Phase I Upgrade of the LHC. The new CMS pixel detector provides four-hit tracking with a reduced material budget as well as new cooling and powering schemes. A new front-end readout chip mitigates buffering and bandwidth limitations, and allows operation at low comparator thresholds. In this paper, comprehensive test beam studies are presented, which have been conducted to verify the design and to quantify the performance of the new detector assemblies in terms of tracking efficiency and spatial resolution. Under optimal conditions, the tracking efficiency is (99.95 ± 0.05) %, while the intrinsic spatial resolutions are (4.80 ± 0.25) μm and (7.99 ± 0.21) μm along the 100 μm and 150 μm pixel pitch, respectively. The findings are compared to a detailed Monte Carlo simulation of the pixel detector and good agreement is found.Peer reviewe

    Performance studies of the CMS strip tracker before installation

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