arXiv subjects

J. Szabelski

Publications and source records attributed to J. Szabelski.

29 records · Page 2Linked to original sources

arXiv2019

The EUSO@TurLab: Test of Mini-EUSO Engineering Model

The TurLab facility is a laboratory, equipped with a 5 m diameter and 1 m depth rotating tank, located in the Physics Department of the University of Turin. Originally, it was mainly built to study systems of different scales where rotation plays a key role in the fluid behavior such as in atmospheric and oceanic flows. In the past few years the TurLab facility has been used to perform experiments related to the observation of Extreme Energy Cosmic Rays (EECRs) from space using the fluorescence technique. For example, in the case of the JEM-EUSO mission, where the diffuse night brightness and artificial light sources can vary significantly in time and space inside the Field of View of the telescope. The Focal Surface of Mini-EUSO Engineering Model (Mini-EUSO EM) with the level 1 (L1) and 2 (L2) trigger logics implemented in the Photo-Detector Module (PDM) has been tested at TurLab. Tests related to the possibility of using an EUSO-like detector for other type of applications such as Space Debris (SD) monitoring and imaging detector have also been pursued. The tests and results obtained within the EUSO@TurLab Project on these different topics are presented.

astro-ph.IM↗

arXiv2017

Design and construction of the POLAR detector

The POLAR detector is a space based Gamma Ray Burst (GRB) polarimeter with a wide field of view, which covers almost half the sky. The instrument uses Compton scattering of gamma rays on a plastic scintillator hodoscope to measure the polarization of the incoming photons. The instrument has been successfully launched on board of the Chinese space laboratory Tiangong~2 on September 15, 2016. The construction of the instrument components is described in this article. Details are provided on problems encountered during the construction phase and their solutions. Initial performance of the instrument in orbit is as expected from ground tests and Monte Carlo simulation.

astro-ph.IM↗

arXiv2017

Instrument Performance and Simulation Verification of the POLAR Detector

POLAR is a new satellite-born detector aiming to measure the polarization of an unprecedented number of Gamma-Ray Bursts in the 50-500 keV energy range. The instrument, launched on-board the Tiangong-2 Chinese Space lab on the 15th of September 2016, is designed to measure the polarization of the hard X-ray flux by measuring the distribution of the azimuthal scattering angles of the incoming photons. A detailed understanding of the polarimeter and specifically of the systematic effects induced by the instrument's non-uniformity are required for this purpose. In order to study the instrument's response to polarization, POLAR underwent a beam test at the European Synchrotron Radiation Facility in France. In this paper both the beam test and the instrument performance will be described. This is followed by an overview of the Monte Carlo simulation tools developed for the instrument. Finally a comparison of the measured and simulated instrument performance will be provided and the instrument response to polarization will be presented.

astro-ph.IM↗

arXiv2017

Calibration of the Space-borne Compton Polarimeter POLAR flight model with 100% polarized X-ray beams

POLAR is space-borne detector designed for a precise measurement of gamma-ray polarization of the prompt emissions of Gamma-Ray Bursts in the energy range 50 keV - 500 keV. POLAR is a compact Compton polarimeter consisting of 40$\times$ 40 plastic scintillator bars read out by 25 multi-anode PMTs. In May 2015, we performed a series of tests of the POLAR flight model with 100\% polarized x-rays beams at the European Synchrotron Radiation Facility beam-line ID11 aming to study thresholds, crosstalk between channels and responses of POLAR flight model to polarized X-ray beams. In this paper we present the data analysis method and some analysis results. According the results, POLAR FM has good polarimetric capabilities.

physics.ins-det↗

arXiv2017

Gain factor and parameter settings optimization of the new gamma-ray burst polarimeter POLAR

As a space-borne detector POLAR is designed to conduct hard X-ray polarization measurements of gamma-ray bursts on the statistically significant sample of events and with an unprecedented accuracy. During its development phase a number of tests, calibrations runs and verification measurements were carried out in order to validate instrument functionality and optimize operational parameters. In this article we present results on gain optimization togeter with verification data obtained in the course of broad laboratory and environmental tests. In particular we focus on exposures to the $^{137}$Cs radioactive source and determination of the gain dependence on the high voltage for all 1600 detection channels of the polarimeter. Performance of the instrument is described in detail with respect to the dynamic range, energy resolution and temperature dependence. Gain optimization algorithms and response non-uniformity studies are also broadly discussed. Results presented below constitute important parts for development of the POLAR calibration and operation database.

astro-ph.IM↗

arXiv2016

POLAR: Final Calibration and In-Flight Performance of a Dedicated GRB Polarimeter

Gamma-ray polarimetry is a new powerful tool to study the processes responsible for the emission from astrophysical sources and the environments in which this emission takes place. Few successful polarimetric measurements have however been performed thus far in the gamma-ray energy band due to the difficulties involved. POLAR is a dedicated polarimeter designed to perform high precision measurements of the polarization of the emission from gamma-ray burst in the 50-500 keV energy range. This new polarimeter is expected to detect approximately 50 gamma-ray bursts per year while performing high precision polarization measurements on approximately 10 bursts per year. The instrument was launched into lower earth orbit as part of the second Chinese space lab, the Tiangong-2, on September 15th 2016 and has been taking data successfully since being switched on one week after. The instrument uses a segmented scintillator array consisting of 1600 plastic scintillator bars, read out by 25 flat-panel multi-anode photomultipliers, to measure the Compton scattering angles of incoming photons. The small segmentation and relatively large uniform effective area allow the instrument to measure the polarization of a large number of transient events, such as gamma-ray bursts, with an unprecedented precision during its two year life-time. The final flight model underwent detailed calibration prior to launch as well as intensive space qualification tests, a summary of which will be presented in this paper. The instrument design will be discussed first followed by an overview of the on-ground tests, finally the in-orbit behavior as measured during the first weeks of the mission will be presented.

astro-ph.IM↗

arXiv2015

Calibration of Gamma-ray Burst Polarimeter POLAR

Gamma Ray Bursts (GRBs) are the strongest explosions in the universe which might be associated with creation of black holes. Magnetic field structure and burst dynamics may influence polarization of the emitted gamma-rays. Precise polarization detection can be an ultimate tool to unveil the true GRB mechanism. POLAR is a space-borne Compton scattering detector for precise measurements of the GRB polarization. It consists of a 40$\times$40 array of plastic scintillator bars read out by 25 multi-anode PMTs (MaPMTs). It is scheduled to be launched into space in 2016 onboard of the Chinese space laboratory TG2. We present a dedicated methodology for POLAR calibration and some calibration results based on the combined use of the laboratory radioactive sources and polarized X-ray beams from the European Synchrotron Radiation Facility. They include calibration of the energy response, computation of the energy conversion factor vs. high voltage as well as determination of the threshold values, crosstalk contributions and polarization modulation factors.

astro-ph.IM↗

arXiv2009

Carpet-3 - a new experiment to study primary composition around the knee

We propose a new experiment to study primary composition around the knee. The Carpet-3 EAS array is the further development of the Carpet-2 EAS array (1700 m a.s.l., Baksan Valley) and it is supposed to be a multi-component and multi-purpose array detecting, in the EASs with $E > 10^{13}$ eV, electrons, gammas, muons (with a threshold energy of 1 GeV), hadrons (with energies more than 30 GeV), and thermal neutrons as well. The experimental data are to be used in the multi-component analysis to make conclusions about the composition of the primary cosmic rays.

astro-ph.IM↗

arXiv2009

Lateral distribution function of high energy muons in EAS around the knee

The lateral distribution function of high energy muons in EAS around the knee ($5.9\le \lg N_e \le 7.1$) has been measured for near vertical showers ($θ\le 20^{\circ}$, effective muon threshold energy is 230 GeV). The measurements have been performed at the Baksan Underground Scintillation Telescope (BUST). The electromagnetic component is measured by the "Andyrchy" EAS array, located above the BUST. The knee in EAS size spectrum is found to be at $\lg N_e \approx 6.3$. The experimental results are compared with Monte Carlo simulations.

astro-ph.HE↗

arXiv1998

High energy hadrons in EAS at mountain altitude

An extensive simulation has been carried out to estimate the physical interpretation of dynamical factors such as , in terms of high energy interaction features, concentrated in the present analysis on the average transverse momentum. It appears that the large enhancement observed for versus primary energy, suggesting in earliest analysis a significant rise of with energy, is only the result of the limited resolution of the detectors and remains in agreement with a wide range of models used in simulations.

hep-ph↗

arXiv1997

Measurable difference in Cherenkov light between gamma and hadron induced EAS

We describe the possibly measurable difference in the Cherenkov light component of EAS induced by an electromagnetic particle (e+, e- or gamma) and induced by a hadron (i.e. proton or heavier nuclei) in TeV range. The method can be applied in experiments which use wavefront sampling method of EAS Cherenkov light detection (e.g. THEMISTOCLE, ASGAT).

astro-ph↗