1. The calibration of the first Large-Sized Telescope of the Cherenkov Telescope ArrayS. Sakurai, Christopher Eckner, Gašper Kukec Mezek, Samo Stanič, Serguei Vorobiov, Lili Yang, Gabrijela Zaharijas, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2019, published scientific conference contribution Abstract: The Cherenkov Telescope Array (CTA) represents the next generation of very high-energy gamma-ray observatory, which will provide broad coverage of gamma rays from 20 GeV to 300 TeV with unprecedented sensitivity. CTA will employ three different sizes of telescopes, and the Large-Sized Telescopes (LSTs) of 23-m diameter dish will provide the sensitivity in the lowest energies down to 20 GeV. The first LST prototype has been inaugurated in October 2018 at La Palma (Canary Islands, Spain) and has entered the commissioning phase. The camera of the LST consists of 265 PMT modules. Each module is equipped with seven high-quantum-efficiency Photomultiplier Tubes (PMTs), a slow control board, and a readout board. Ensuring high uniformity and precise characterization of the camera is the key aspects leading to the best performance and low systematic uncertainty of the LST cameras. Therefore, prior to the installation on site, we performed a quality check of all PMT modules. Moreover, the absolute calibration of light throughput is essential to reconstruct the amount of light received by the telescope. The amount of light is affected by the atmosphere, by the telescope optical system and camera, and can be calibrated using the ring-shaped images produced by cosmic-ray muons. In this contribution, we will show the results of off-site quality control of PMT modules and on-site calibration using muon rings. We will also highlight the status of the development of Silicon Photomultiplier modules that could be considered as a replacement of PMT modules for further improvement of the camera. Keywords: very-high-energy gamma-ray astronomy, Cherenkov Telescope Array (CTA) Observatory, Large-Sized Telescopes (LSTs), LST-1 calibration, Photomultiplier Tubes (PMTs) Published in RUNG: 14.11.2024; Views: 288; Downloads: 4 Full text (3,10 MB) This document has many files! More... |
2. The Cherenkov transparency coefficient for the atmospheric monitoring and array calibration at the Cherenkov Telescope Array SouthStanislav Stefanik, Christopher Eckner, Gašper Kukec Mezek, Samo Stanič, Serguei Vorobiov, Lili Yang, Gabrijela Zaharijas, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2019, published scientific conference contribution Abstract: Reconstruction of energies of very-high-energy γ–rays observed by imaging atmospheric Cherenkov telescopes is affected by changes in the atmospheric conditions and the performance of telescope components. Reliable calibration schemes aimed at these effects are necessary for the forthcoming Cherenkov Telescope Array (CTA) to achieve its goals on the maximally allowed systematic uncertainty of the global energy scale. A possible means of estimating the atmospheric attenuation of Cherenkov light is the method of the Cherenkov transparency coefficient (CTC). The CTC is calculated using the telescope detection rates, dominated by the steady cosmic ray background, while properly correcting for the hardware and observational conditions.
The coefficient can also be used to relatively calibrate the optical throughput of telescopes on the assumption of homogeneous atmospheric transparency above the array. Using Monte Carlo simulations, we investigate here the potential of the CTC method for the atmospheric monitoring and telescope cross-calibration at the CTA array in the southern hemisphere. We focus on the feasibility of the method for the array of telescopes of three sizes in different observation configurations and under various levels of atmospheric attenuation. Keywords: very-high-energy gamma-ray astronomy, Cherenkov Telescope Array (CTA) Observatory, imaging atmospheric Cherenkov telescopes (IACTs), atmospheric monitoring, IACT calibration Published in RUNG: 14.11.2024; Views: 294; Downloads: 4 Full text (1,90 MB) This document has many files! More... |
3. Using muon rings for the optical throughput calibration of the Cherenkov Telescope ArrayMarkus Gaug, Christopher Eckner, Gašper Kukec Mezek, Samo Stanič, Serguei Vorobiov, Lili Yang, Gabrijela Zaharijas, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2019, published scientific conference contribution Abstract: Muon ring images observed with Imaging Atmospheric Cherenkov Telescopes (IACTs) provide a powerful means to calibrate the optical throughput of IACTs and monitor their optical point spread function. We investigate whether muons ring images can be used as the primary optical throughput calibration method for the telescopes of the future Cherenkov Telescope Array (CTA) and find several additional systematic effects in comparison to previous works. To ensure that the method achieves the accuracy required by CTA, these systematic effects need to be taken into account and minor modifications to the hardware and analysis are necessary. We derive analytic estimates for the expected muon data rates to be used for optical throughput calibration, monitoring of the optical point spread function, with achievable statistical and systematic uncertainties, and explore the potential of muon ring images as a secondary method of camera pixel flat-fielding. Keywords: very-high-energy gamma-ray astronomy, Cherenkov Telescope Array (CTA) Observatory, Imaging Atmospheric Cherenkov Telescopes, IACT optical throughput calibration, IACT camera pixel flat-fielding, IACT optical point spread function (PSF), muon ring images Published in RUNG: 13.11.2024; Views: 308; Downloads: 5 Full text (247,77 KB) This document has many files! More... |
4. The Joint Aeolus Tropical Atlantic Campaign 2021/2022 overview : atmospheric science and satellite validation in the tropicsThorsten Fehr, Griša Močnik, 2023, published scientific conference contribution abstract Abstract: ESA’s Aeolus satellite observations are expected to have the biggest impact for the improvement of numerical weather prediction in the Tropics. An important case relating to the predictability of tropical weather systems is the outflow of Saharan dust, its interaction with cloud microphysics and impact on the development of tropical storms over the Atlantic Ocean.The Joint Aeolus Tropical Atlantic Campaign (JATAC) deployed on Cabo Verde (2021/2022) and the US Virgin Islands (2021) supported the validation and preparation of the ESA missions Aeolus, EarthCARE and WIVERN, and addressed science objectives regarding the Saharan Aerosol layer, African Easterly Waves and Jet, Tropical Easterly Jet, and the Intertropical Convergence Zone, as well as their relation to the formation of convective systems, and the long-range transport of dust and its impact on air quality.JATAC started in July 2021 with the deployment of ground-based instruments in the frame of the ASKOS project at the Ocean Science Center Mindelo, including the eVe and PollyXT lidars, and a W-band Doppler cloud radar. By mid-August, the CPEX-AW campaign started operations from the US Virgin Islands with NASA’s DC-8 flying laboratory in the Western Tropical Atlantic and Caribbean carrying the Doppler Aerosol Wind Lidar (DAWN), Airborne Precipitation and Cloud Radar (APR-3), Water Vapor DIAL and HSRL (HALO), microwave sounder (HAMSR) and dropsondes. In September the DLR Falcon-20 aircraft, carrying the ALADIN Airborne Demonstrator (A2D) and the 2-µm Doppler wind lidar, and the Safire Falcon-20, carrying the high-spectral-resolution Doppler lidar (LNG), the RASTA Doppler cloud radar, in-situ cloud and aerosol instruments, and dropsondes, were deployed to Sal in the frame of the AVATAR-T and CADDIWA projects. The Aerovizija Advantic WT-10 light aircraft with optical particle spectrometers, filter-photometers and nephelometers for in-situ aerosol characterisation was operating in close coordination with the ground-based observations in the CAVA-AW project.The activities continued in June 2022 when the ASKOS ground based observations were enhanced with UAV airborne in-situ aerosol measurements deployed by the Cyprus Institute, solar radiation measurements supported by PMOD/WRC, dust particle orientation measurements (WALL-E lidar), and radiosonde releases equipped with electric field-mills. NASA deployed the DC-8 aircraft all September to Sal with the 2021 payload in the framework of the CPEX-CV activity, including regular radiosonde launches. As in 2021, the Aerovizija aircraft took part with in-situ aerosol measurements during two weeks in September. JATAC was supported by dedicated numerical weather and dust simulations supporting forecasting efforts and addressing open science questions.Around 60 scientific flights of four aircraft, with an additional 25 UAV flights, were performed during JATAC. 23 Aeolus orbits were underflown, many of them with simultaneous observations of multiple aircraft collocated with ground-based observations. In addition, the science objectives were fully covered through the large number of flights, ground based cloud and aerosol observations, regular radiosondes and dropsondes.Overall, JATAC activities have resulted in a high-quality and comprehensive dataset supporting a wide range of tropical atmospheric research, the validation of Aeolus and other satellites, and have provided key reference data for the development future Earth Observation missions. Keywords: Aeolus satellite, airborne measurements, mineral dust, cal/val, calibration, validation Published in RUNG: 21.12.2023; Views: 1780; Downloads: 5 Full text (293,23 KB) This document has many files! More... |
5. Effect of optical properties of FDs on reconstruction analysisDaiki Sato, R. U. Abbasi, Y. Abe, T. Abu-Zayyad, M. Allen, Yasuhiko Arai, R. Arimura, E. Barcikowski, J. W. Belz, Douglas R. Bergman, 2023, published scientific conference contribution Abstract: The TA experiment uses fluorescence telescopes to observe cosmic ray air showers. The telescope camera uses PMTs as Pixels. The telescope’s PMT pointing direction has an uncertainty of 0.1°, and more precise measurements of the telescope's optical properties are needed to more accurately reconstruct the cosmic ray air showers. We have developed the Opt-copter which is a light source mounted on a drone that can be flown within the telescope's field of view. Observational experiments with the Opt-copter have provided a more accurate analysis of the telescope viewing direction.
In this study, we estimate the effect of this measurement of accurate telescope viewing direction on the reconstruction of cosmic ray air showers. Keywords: Telescope Array, indirect detection, fluorescence detection, ultra-high energy, cosmic rays, composition, calibration, Xmax Published in RUNG: 10.10.2023; Views: 1852; Downloads: 7 Full text (670,84 KB) This document has many files! More... |
6. FOV direction and image size calibration of Fluorescence Detector using light source on UAVA. Nakazawa, Jon Paul Lundquist, 2022, published scientific conference contribution Abstract: In the Telescope Array (TA) experiment, we have been observing cosmic rays using a Fluorescence Detector (FD). More than 10 years have passed since we started this observation, and the accuracy of the observation has become more important than ever. We have developed the "Opt-copter" as a calibration device for the FDs. The Opt-copter is an unmanned aerial vehicle (UAV) equipped with a light source and can fly freely within the FD's field of view (FOV). In addition, the Opt-copter is equipped with a high-precision RTK-GPS, which enables it to accurately determine the position of the light source in flight. With this device, we can obtain detailed information on the optical characteristics of the FD. So far, we have reported on the configuration of the device and the analysis of the FOV direction. In this presentation, we will report on the new FOV analysis and image size analysis. Keywords: Telescope Array, indirect detection, fluorescence detection, ultra-high energy, cosmic rays, light source, calibration, UAV, FOV Published in RUNG: 04.10.2023; Views: 2314; Downloads: 8 Full text (7,14 MB) This document has many files! More... |
7. JATAC/CAVA-AW Aeolus Cal/Val airborne campaign datasetJesús Yus-Díez, Griša Močnik, Luka Drinovec, Marija Bervida, Blaž Žibert, Uroš Jagodič, Matevž Lenarčič, complete scientific database of research data Abstract: Light aircraft (WT10 - experimental) with position and windspeed variables provided by onboard GPS, as well as additional meteorological sensors. The aircraft was mounted with a: a sunshine pyranometer type SPN1 (Delta-T Devices Ltd), a polar integrating nephelometer AURORA 4000 (Ecotech Pty Ltd), and had a dual sampling line aircraft for measurements at the fine and coarse fraction of the absorption by two Continuous Light Absorption Photometer (CLAPS, by Haze Instruments d.o.o.) and the particle size distribution by two optical particle counters (OPC, model 11D, GRIMM Technologies). The pyranometer provides measurements of the global, direct and diffuse irradiance for a radiation spectrum range between 400 and 2700nm with a 1s time resolution. The polar integrating nephelometer measures the scattering coefficients of particles at three wavelengths (450, 525 and 635 nm) and multiple angles (two selected for the campaign: 0, 90deg) with a 5s time resolution. The CLAP photometers measure the absorption coefficient by aerosol particles at three wavelengths (467, 529 and 653 nm) with a 1s time resolution. The OPC measurements provide the number and mass concentration of aerosol particles for 31 bins in the size range between 0.253 and 35.15 micrometers with a 6s time resolution.
The 2021 and 2022 campaigns are found at:
http://www.worldgreenflight.com/glwf.php#to-2021
http://www.worldgreenflight.com/glwf.php#to-2022-jatac Keywords: Aeolus satellite, Saharan dust, aerosol, calibration, validation Published in RUNG: 27.09.2023; Views: 1806; Downloads: 13 Full text (77,35 KB) This document has many files! More... |
8. THE CALIBRATION PROCESS OF A MANUFACTURING LINE IN THE AUTOMOTIVE INDUSTRYAleksandar Kuzmanovski, 2022, undergraduate thesis Abstract: Calibration of measuring instruments in the industry is a process that is done regularly both internally by internal laboratories operating within the companies and externally by accredited external laboratories. The goal of the diploma thesis was to document and carry out the calibration process of a production line within a manufacturing plant, and to deliver a final report on the overall calibration.
The result is obtained by calculating the combined uncertainty of the measurement process. As any measurement is gathered certain uncertainties are bound to influence the measurements, in our case we have three main uncertainties which are the standard uncertainty, uncertainty due to the resolution of the measuring instrument and the uncertainty from the calibration certificate from the measuring equipment that is used in the measurement process.
The final combined uncertainty is calculated with the standard uncertainty which has a 68% confidence that the true value lies within that range therefore we need to expand the range to obtain a 95% confidence and we achieve this by multiplication of the combined uncertainty with the K = 2 factor. Keywords: Metrology, calibration, adjustment, measurement errors, measurement uncertainty, measuring instruments, measuring equipment. Published in RUNG: 05.01.2023; Views: 2301; Downloads: 46 Full text (2,07 MB) |
9. A dual-wavelength photothermal aerosol absorption monitor : design, calibration and performanceLuka Drinovec, Uroš Jagodič, Luka Pirker, Miha Škarabot, Mario Kurtjak, Kristijan Vidović, Luca Ferrero, Bradley Visser, Jannis Röhrbein, Ernest Weingartner, Daniel M. Kalbermatter, Konstantina Vasilatou, Griša Močnik, 2022, original scientific article Abstract: There exists a lack of aerosol absorption measurement techniques with low uncertainties and without artefacts. We have developed the two-wavelength Photothermal Aerosol Absorption Monitor (PTAAM-2λ), which measures the aerosol absorption coefficient at 532 and 1064 nm. Here we describe its design, calibration and mode of operation and evaluate its applicability, limits and uncertainties. The 532 nm channel was calibrated with ∼ 1 µmol mol−1 NO2, whereas the 1064 nm channel was calibrated using measured size distribution spectra of nigrosin particles and a Mie calculation. Since the aerosolized nigrosin used for calibration was dry, we determined the imaginary part of the refractive index of nigrosin from the absorbance measurements on solid thin film samples. The obtained refractive index differed considerably from the one determined using aqueous nigrosin solution. PTAAM-2λ has no scattering artefact and features very low uncertainties: 4 % and 6 % for the absorption coefficient at 532 and 1064 nm, respectively, and 9 % for the absorption Ångström exponent. The artefact-free nature of the measurement method allowed us to investigate the artefacts of filter photometers. Both the Aethalometer AE33 and CLAP suffer from cross-sensitivity to scattering – this scattering artefact is most pronounced for particles smaller than 70 nm. We observed a strong dependence of the filter multiple scattering parameter on the particle size in the 100–500 nm range. The results from the winter ambient campaign in Ljubljana showed similar multiple scattering parameter values for ambient aerosols and laboratory experiments. The spectral dependence of this parameter resulted in AE33 reporting the absorption Ångström exponent for different soot samples with values biased 0.23–0.35 higher than the PTAAM-2λ measurement. Photothermal interferometry is a promising method for reference aerosol absorption measurements. Keywords: aerosol absorption, calibration, black carbon Published in RUNG: 28.06.2022; Views: 2137; Downloads: 26 Link to full text This document has many files! More... |
10. Calibration of the underground muon detector of the Pierre Auger ObservatoryA. Aab, Andrej Filipčič, Jon Paul Lundquist, Samo Stanič, Marta Trini, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2021, original scientific article Abstract: To obtain direct measurements of the muon content of extensive air showers with energy above 10[sup]16.5 eV, the Pierre Auger Observatory is currently being equipped with an underground muon detector (UMD), consisting of 219 10 m[sup]2-modules, each segmented into 64 scintillators coupled to silicon photomultipliers (SiPMs). Direct access to the shower muon content allows for the study of both of the composition of primary cosmic rays and of high-energy hadronic interactions in the forward direction. As the muon density can vary between tens of muons per m[sup]2 close to the intersection of the shower axis with the ground to much less than one per m[sup]2 when far away, the necessary broad dynamic range is achieved by the simultaneous implementation of two acquisition modes in the read-out electronics: the binary mode, tuned to count single muons, and the ADC mode, suited to measure a high number of them. In this work, we present the end-to-end calibration of the muon detector modules: first, the SiPMs are calibrated by means of the binary channel, and then, the ADC channel is calibrated using atmospheric muons, detected in parallel to the shower data acquisition. The laboratory and field measurements performed to develop the implementation of the full calibration chain of both binary and ADC channels are presented and discussed. The calibration procedure is reliable to work with the high amount of channels in the UMD, which will be operated continuously, in changing environmental conditions, for several years. Keywords: ultra-high energy cosmic rays, extensive air showers (EAS), EAS muonic component, Pierre Auger Observatory, underground muon detector, detector calibration Published in RUNG: 14.04.2021; Views: 3579; Downloads: 140 Link to full text This document has many files! More... |