Optical filter

An optical filter is a device that selectively transmits light of different wavelengths, usually implemented as a glass plane or plastic device in the optical path, which are either dyed in the bulk or have interference coatings. The optical properties of filters are completely described by their frequency response, which specifies how the magnitude and phase of each frequency component of an incoming signal is modified by the filter. Filters mostly belong to one of two categories. The simplest, physically, is the absorptive filter; then there are interference or dichroic filters. Many optical filters are used for optical imaging and are manufactured to be transparent; some used for light sources can be translucent. Optical filters selectively transmit light in a particular range of wavelengths, that is, colours, while absorbing the remainder. They can usually pass long wavelengths only (longpass), short wavelengths only (shortpass), or a band of wavelengths, blocking both longer a

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Implementation of FIR filters for fast multi-channel processing

Corentin Ferry

Digital signal processors are ubiquitous in electronics, with applications ranging from sound processing to software-defined radio. Finite impulse response (FIR) filters are among the components that are used for the processing; the implementation is tailored to the user’s needs, whether they specifically need performance or configurability. Handling numerous channels in a single filter block can be achieved in hardware by running multiple filters in parallels, with a high space expense and controller overhead. This project proposes and discusses an implementation template for a pipeline that simultaneously processes a desired number of channels, while keeping coefficients configurability. The implementation we propose is economic in terms of area while meeting the theoretical timing requirements to process long filters.

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The radiation field in the Gamma Irradiation Facility GIF plus plus at CERN

Georgi Gorine, Federico Ravotti

The high-luminosity LHC (HL-LHC) upgrade is setting now a new challenge for particle detector technologies. The increase in luminosity will produce a particle background in the gas-based muon detectors that is ten times higher than under conditions at the LHC. The detailed knowledge of the detector performance in the presence of such a high background is crucial for an optimized design and efficient operation after the HL-LHC upgrade. A precise understanding of possible aging effects of detector materials and gases is of extreme importance. To cope with these challenging requirements, a new Gamma Irradiation Facility (GIF++) was designed and built at the CERN SPS North Area as successor of the Gamma Irradiation Facility (GIF) during the Long Shutdown 1 (LS1) period. It features an intense source of 662 keV photons with adjustable intensity, to simulate continuous background over large areas, and, combined with a high energy muon beam, to measure detector performance in the presence of the background. The new GIF++ facility has been operational since spring 2015. In addition to describing the facility and its infrastructure, the goal of this work is to provide an extensive characterization of the GIF++ photon field with different configurations of the absorption filters in both the upstream and downstream irradiation areas. Moreover, the measured results are benchmarked with Geant4 simulations to enhance the knowledge of the radiation field. The absorbed dose in air in the facility may reach up to 2.2 Gy/h directly in front of the irradiator. Of special interest is the low-energy photon component that develops due to the multiple scattering of photons within the irradiator and from the concrete walls of the bunker. (C) 2017 The Authors. Published by Elsevier B.V.

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Real-time Java simulations of multiple interference dielectric filters

Olivier Martin

An interactive Java applet for real-time simulation and visualization Of the transmittance properties of multiple interference dielectric filters is presented. The Most commonly used interference filters as well as the state-of-the-art ones are embedded in this platform-independent applet which call serve research and education purposes. The Transmittance applet call be freely downloaded from the site http://cpc.cs.qub.ac.uk.

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Photographic filter

In photography and cinematography, a filter is a camera accessory consisting of an optical filter that can be inserted into the optical path. The filter can be of a square or oblong shape and mounte

Mirror

A mirror or looking glass is an object that reflects an . Light that bounces off a mirror will show an image of whatever is in front of it, when focused through the lens of the eye or a camera. Mi

Dichroic filter

A dichroic filter, thin-film filter, or interference filter is a color filter used to selectively pass light of a small range of colors while reflecting other colors. By comparison, dichroic mirrors