Radio-optical line for SCADA systems with relay Krasnov, R P; Ostankov, A V; Malyshev, I I ...
IOP conference series. Materials Science and Engineering,
05/2020, Letnik:
862, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Hybrid optical-radio communication systems provide high-speed access within the "last mile" and can act as highly reliable broadband channels of SCADA software and hardware systems. They use optical ...channels as the main communication lines, and radio channels as backup, since the transmission quality of atmospheric optical channels is largely determined by weather conditions. To reduce the effect of atmospheric turbulence, it is proposed to use the option of spatial diversity with line-of-sight channels and containing a repeater. When the signal-to-noise ratio decreases in the optical channel below the selected threshold, switching to the radio link is to be performed. The paper provides the results of modeling the operation of a hybrid radio-optical line in SCADA systems, in which a new switching system for optical and radio-frequency channels using a repeater is proposed. The dependences of the outage probability of the optical channel and the system as a whole are obtained.
Based on the investigation of Lower-Middle Jurassic sediments in SW Siberia, isochron reference clay and coal horizons confined to the roof of chronostratigraphic units were identified; bed series ...from pre-Jurassic formation bottom to U sub(10) coal layer were divided; structural features and distribution of regional cyclites J sub(10)-J sub(17) in the sequences and throughout the area were determined.
The time resolution of the prototype counters for a new charged particle hodoscope for the NA62 experiment has been measured. The prototype scintillation counters with dimensions of 90 × 90, 100 × ...100, 150 × 150, 180 × 100, and 270 × 100 mm are investigated. Several variants of direct light collection from a scintillator brink and a corner are considered, as well as light collection using wavelength-shifting (WLS) fibers. Silicon photodiodes from the Centre of Perspective Technologies and Apparatuses (CPTA) and SensL, as well as a compact R7400U photomultiplier tube were used as photodetectors. An R7899-20 photomultiplier tube with a high quantum efficiency in the green spectral region is used as a reference counter. The measurements have been taken with cosmic muons and the beam halo of beamline 21 in the zone of the OKA experiment. The time resolution of a 100 × 100 mm cell, averaged over the area, is 590 ± 10 ps in the case of the WLS-fiber readout and 260 ± 25 ps in the case of direct light collection from the scintillator brink.
The image camera of the 17
m ∅ MAGIC telescope, an air Cherenkov telescope currently under construction to be installed at the Canary island La Palma, is described. The main goal of the experiment is ...to cover the unexplored energy window from ∼10 to ∼300
GeV in γ-ray astrophysics. In its first phase with a classical PMT camera the MAGIC telescope is expected to reach an energy threshold of ∼30
GeV. The operational conditions, the special characteristics of the developed PMTs and their use with light concentrators, the fast signal transfer scheme using analog optical links, the trigger and DAQ organization as well as image reconstruction strategy are described. The different paths being explored towards future camera improvements, in particular the constraints in using silicon avalanche photodiodes and GaAsP hybrid photodetectors in air Cherenkov telescopes are discussed.
A simple method to enhance the sensitivity of photomultipliers (PMTs) will be described. The method is based on applying onto the cathode window a specially prepared lacquer containing a wavelength ...shifter (WLS). A rapidly evaporating lacquer solvent results in a milky surface that acts as a photon scatterer. Applying the method to the ET 9116A PMT (hemispherical borosilicate window and rubidium-bialkali photocathode) resulted in a good sensitivity in the short-wave UV range as well as a ≳20% increase above 330nm. Details of the study, the procedure and a simple model for the explanation of the enhancement are presented.
A 17-m-diameter air Cherenkov telescope, dubbed MAGIC, for ground-based gamma-ray astronomy above 30 GeV is under construction on the Canary Island of La Palma. The 577-pixel photomultiplier camera ...requires precise and regular calibration over a large dynamic range. A system for the optical calibration consisting of a number of very fast and powerful light emitting diode light pulsers is presented. We intend to calibrate each individual pixel up to 2000-3000 photoelectrons with different wavelengths, e.g. 370, 460, and 520 nm. We aim to achieve an absolute calibration at these three wavelengths by comparing the signal of the pixels with the one of specially prepared and calibrated photomultipliers and, at a later stage, hybrid photon detectors operated in single photon counting mode and with the use of well-calibrated attenuation filters ("blind pixels"). The light flux of the pulser is cross calibrated by a 1 cm/sup 2/ PIN diode (Hamamatsu), read out via a charge sensitive preamplifier. The PIN diode is calibrated with 60-keV gammas (from an Am 241 source) producing a precise signal of 16 570 electron-hole pairs. In addition, there will be a computer adjustable continuous light source to simulate and calibrate the response of the PMTs in the camera to the moon and the light of the night sky. This will also help to handle starlight in the field of view of the camera during analysis. Special attention is paid toward building a robust field usable device complying with IP 65 standards (sealed against heavy jet spray and dust).
A study of the new hemispherical 6-dynodes PMT from electron tubes Ostankov, A.; Paneque, D.; Lorenz, E. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2000, Letnik:
442, Številka:
1-3
Journal Article
Recenzirano
The main electro-optical properties of the new fast and low-gain hemispherical PMT from Electron Tubes Ltd. have been studied. This PMT is considered as photosensor for the camera of the 17m diameter ...air Cherenkov telescope MAGIC to be installed in two years at Canary Island La Palma. The dependence of the single-electron resolution and afterpulse rates as well as linearity on the interdynode voltages have been studied in detail.
Ultrafast Flash amplitude-to-digital converters (FADCs) are still very expensive. Here we propose a multiplexing scheme allowing one in common trigger mode to read out multiple signal sources by ...using a single FADC channel. Usual coaxial cables can be used in the multiplexer as analog signal delay elements. The limited bandwidth of the coaxial cable, depending on its type and length will set an upper limit to the number of multiplexed channels. Better bandwidth and the correspondingly higher number of multiplexed channels one can obtain when using the technique of transmission of analog signals via optical fibers. Low-cost vertical cavity surface emitting laser (VCSEL) diodes can be used as converters of fast electrical signals into near infrared light. Multiplexing can be an economically priced solution when one needs ultrafast digitization of hundreds of fast signal channels.
The results of a partial wave analysis of 3π system produced in the reaction
π
−
A →
π
+
π
−
π
−
A at the momentum of 36.6 GeV/c on beryllium target are presented. Resonant signals from
a′
1(1750),
a
...3(1860),
a
4(2050) are observed in different channels. Small bump at
M ≈ 1.6GeV in the exotic wave
J
PC
M
η
= 1
−+1
+ is seen. The combined analysis of VES data on this wave in η′π,
b
1(1235)
π and ϱπ channels points to the existence of a hybrid meson with
M ≈ 1.6 GeV.
Constraints in using APDs in air Cherenkov telescopes for γ-astronomy Martinez, M; Ostankov, A; Lorenz, E ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2000, Letnik:
442, Številka:
1-3
Journal Article
Recenzirano
The constraints in using APDs for future air Cherenkov telescope cameras due to the limited gain and the different electronic noise sources are discussed. Different operational strategies are ...presented. It is shown that in spite of the limitation to resolve single photons these devices could be used in future image cameras of Cherenkov telescopes.
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