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1.
Active Galactic Nuclei population studies with the Cherenkov Telescope Array
Anthony M. Brown, Saptashwa Bhattacharyya, Barbara MARČUN, Judit Pérez Romero, Samo Stanič, Veronika Vodeb, Serguei Vorobiov, Gabrijela Zaharijas, Marko Zavrtanik, Danilo Zavrtanik, Miha Živec, 2021, published scientific conference contribution

Abstract: The Cherenkov Telescope Array (CTA) observatory is the next generation of ground-based imaging atmospheric Cherenkov telescopes (IACTs). Building on the strengths of current IACTs, CTA is designed to achieve an order of magnitude improvement in sensitivity, with unprecedented angular and energy resolution. CTA will also increase the energy reach of IACTs, observing photons in the energy range from 20 GeV to beyond 100 TeV. These advances in performance will see CTA heralding in a new era for high-energy astrophysics, with the emphasis shifting from source discovery, to population studies and precision measurements. In this talk we discuss CTA’s ability to conduct source population studies of �-ray bright active galactic nuclei and how this ability will enhance our understanding on the redshift evolution of this dominant �-ray source class.
Keywords: Cherenkov Telescope Array, high-energy astrophysics, active galactic nuclei
Published in RUNG: 19.09.2023; Views: 1558; Downloads: 7
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2.
Taming the topology of calix[4]arene-based 2D-covalent organic frameworks : interpenetrated vs noninterpenetrated frameworks and their selective removal of cationic dyes
Bikash Garai, Dinesh Shetty, Tina Škorjanc, Felipe Gándara, Nawavi Naleem, Sabu Varghese, Sudhir Kumar Sharma, Maria Baias, Ramesh Jagannathan, Mark Anthony Olson, 2021, original scientific article

Abstract: A bowl-shaped calix[4]arene with its exciting host–guest chemistry is a versatile supramolecular building block for the synthesis of distinct coordination cages or metal–organic frameworks. However, its utility in the synthesis of crystalline covalent organic frameworks (COFs) remains challenging, presumably due to its conformational flexibility. Here, we report the synthesis of a periodic 2D extended organic network of calix[4]arenes joined by a linear benzidine linker via dynamic imine bonds. By tuning the interaction among neighboring calixarene units through varying the concentration in the reaction mixture, we show the selective formation of interpenetrated (CX4-BD-1) and non-interpenetrated (CX4-BD-2) frameworks. The cone-shaped calixarene moiety in the structural backbone allows for the interweaving of two neighboring layers in CX4-BD-1, making it a unique example of interpenetrated 2D layers. Due to the high negative surface charge from calixarene units, both COFs have shown high performance in charge-selective dye removal and an exceptional selectivity for cationic dyes irrespective of their molecular size. The charge distribution of the COFs and the resulting selectivity for the cationic dyes were further investigated using computational methods.
Keywords: dyes and pigments, covalent organic frameworks, adsorption, layers, chemical structure
Published in RUNG: 16.03.2021; Views: 3018; Downloads: 0
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3.
e/p separation study using the ISS-CREAM top and bottom counting detectors
S. C. Kang, Y. Amarea, D. Angelaszek, N. Anthony, G. H. Choi, M. Chung, M. Copley, L. Derome, L. Eraud, C. Falana, Jon Paul Lundquist, 2019, published scientific conference contribution

Abstract: Cosmic Ray Energetics And Mass for the International Space Station (ISS-CREAM) is an experiment for studying the origin, acceleration, and propagation mechanisms of high-energy cosmic rays. The ISS-CREAM instrument was launched on the 14th of August 2017 to the ISS aboard the SpaceX-12 Dragon spacecraft. The Top and Bottom Counting Detectors (TCD/BCD) are parts of the ISS-CREAM instrument and designed for studying electron and gamma-ray physics. The TCD/BCD each consist of an array of 20 × 20 photodiodes on a plastic scintillator. The TCD/BCD can separate electrons from protons by using the difference between the shapes of electromagnetic and hadronic showers in the high energy region. The Boosted Decision Tree (BDT) method, which is a deep learning method, is used in this separation study. We will present results of the electron/proton separation study and rejection power in various energy ranges.
Keywords: instrumentations, high energy cosmic rays, particle detectors, composition
Published in RUNG: 08.02.2021; Views: 3145; Downloads: 0
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4.
On-orbit performance of the ISS-CREAM calorimeter
K. C. Kim, Y. Amarea, D. Angelaszek, N. Anthony, G. H. Choi, M. Chung, M. Copley, L. Derome, L. Eraud, C. Falana, Jon Paul Lundquist, 2019, published scientific conference contribution

Abstract: Cosmic Ray Energetics And Mass for the International Space Station (ISS-CREAM) experiment is designed to study the composition and energy spectra of cosmic-ray particles from 10^12 to 10^15 eV. ISS-CREAM was launched and deployed to the ISS in August 2017. The ISS-CREAM payload employs a Silicon Charge Detector for charge measurements, Top and Bottom Counting Detector for electron-hadron separation and a low-energy trigger, a Boronated Scintillator Detector for additional electron-hadron separation, and a Calorimeter (CAL) for en-ergy measurements and a high-energy trigger. The CAL is constructed of 20 layers of tungsten plates interleaved with scintillating fiber ribbons read out by hybrid-photodiodes (HPDs) and densified carbon targets. Each CAL layer is made of 3.5 mm (1 X_0) thick tungsten plates alter-nating with fifty 0.5 mm thick and 1 cm wide scintillating fiber ribbons. Consecutive layers of fiber ribbons are installed orthogonal to each other. Energy deposition in the CAL determines the particle energy and provides tracking information to determine which segment(s) of the charge detectors to use for the charge measurement. Tracking for showers is accomplished by extrapolating each shower axis back to the charge detectors. The performance of the ISS-CREAM CAL during flight is presented.
Keywords: instrumentations, high energy cosmic rays, particle detectors
Published in RUNG: 08.02.2021; Views: 3413; Downloads: 0
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5.
ISS-CREAM flight operation
K. C. Kim, Y. Amarea, D. Angelaszek, N. Anthony, G. H. Choi, M. Chung, M. Copley, L. Derome, L. Eraud, C. Falana, Jon Paul Lundquist, 2019, published scientific conference contribution

Abstract: The Cosmic Ray Energetics And Mass experiment for the International Space Station (ISS-CREAM) is designed and built to measure the elemental energy spectra of cosmic-ray particles (1 ≤ Z ≤ 26) and electrons. It measures the energy of incident cosmic rays from 10^12 to 10^15 eV. ISS-CREAM was launched and deployed to the ISS in August 2017. The Science Operations Center (SOC) at the University of Maryland has been operating the payload on the International Space Station (ISS) in coordination with the Payload Operations Integration Center (POIC) at NASA’s Marshall Space Flight Center. The SOC has been responsible for sending commands to and receiving data from the Science Flight Computer (SFC) on board ISS-CREAM. The ISS-CREAM data taking program interfaces with the POIC using the Telescience Resources Kit through the Software Toolkit for Ethernet Lab-Like Architecture developed by the Boeing Company. The command uplink and data downlink have been through the Track-ing and Data Relay Satellite System. We present the ISS-CREAM flight operations including ISS communications, SFC performance, etc.
Keywords: instrumentations, high energy cosmic rays, particle detectors
Published in RUNG: 08.02.2021; Views: 3244; Downloads: 0
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6.
On-orbit performance of the ISS-CREAM SCD
G. H. Choi, Y. Amarea, D. Angelaszek, N. Anthony, M. Chung, M. Copley, L. Derome, L. Eraud, C. Falana, Jon Paul Lundquist, 2019, published scientific conference contribution

Abstract: The Cosmic Ray Energetic And Mass for the International Space Station (ISS-CREAM) experiment is designed for precision measurements of energy spectra and elemental composition of cosmic rays. It was launched and installed on the ISS in August 2017. The Silicon Charge Detector (SCD), placed at the top of the ISS-CREAM payload, consists of 4 layers with a total of 10,752 silicon pixels which have 1.37 × 1.57 cm^2 size each. Each layer is arranged in such a fashion that its active detection area of 78 × 74 cm^2 is free of any dead area. The SCD 4-layer configuration was chosen to achieve the best precision in measuring the charge of cosmic rays from proton to iron nuclei with a charge resolution of 0.1 − 0.3e. We will present its on-orbit performance and operation status on the ISS since the launch.
Keywords: instrumentations, high energy cosmic rays, particle detectors
Published in RUNG: 08.02.2021; Views: 3133; Downloads: 0
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7.
Monte Carlo simulations of the ISS-CREAM instrument
J. Wu, Y. Amarea, D. Angelaszek, N. Anthony, G. H. Choi, M. Chung, M. Copley, L. Derome, L. Eraud, Jon Paul Lundquist, 2019, published scientific conference contribution

Abstract: Cosmic Ray Energetics and Mass for the International Space Station (ISS-CREAM) is designed to directly measure the energy spectra of high-energy cosmic rays, encompassing proton to iron nuclei, over the energy range from 1012 to 1015 eV [1]. The capability to measure an extended energy range enables us to probe the origin and acceleration mechanisms of cosmic rays. The ISS-CREAM instrument is configured with the balloon-borne CREAM calorimeter (CAL) for energy measurements and four layers of a finely segmented Silicon Charge Detector (SCD) for charge measurements. In addition, two new compact detectors have been developed for electron/proton separation: Top and Bottom scintillator-based counting detectors (TCD/BCD) and a boronated scintillator detector (BSD). Simulations use the GEANT3 package [2] with the FLUKA hadronic model [3]. An isotropic event generator was developed for the ISS-CREAM geometry with particles incident from the upper hemisphere. We will present simulation results regarding ISS-CREAM performance, including trigger rates, energy resolution, energy response, tracking resolution, charge efficiency, etc.
Keywords: instrumentations, detectors, Monte Carlo
Published in RUNG: 05.02.2021; Views: 3067; Downloads: 0
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