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1.
Azimuthal asymmetry in the risetime of the Surface Detector signals of the Pierre Auger Observatory
Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Ignacio Minaya, 2015, objavljeni znanstveni prispevek na konferenci

Opis: The azimuthal asymmetry in the risetime of signals in Auger surface detector stations is a source of information on shower development. The azimuthal asymmetry is due to a combination of the longitudinal evolution of the shower and geometrical effects related to the angles of incidence of the particles into the detectors. The magnitude of the effect depends upon the zenith angle and state of development of the shower and thus provides a novel observable sensitive to the mass composition of cosmic rays above 3 × 10[sup]18 eV. By comparing measurements with predictions from shower simulations, we find for both of our adopted models of hadronic physics (QGSJetII- 04 and Epos-LHC) an indication that the mean cosmic-ray mass increases with energy, as has been inferred from other studies. However the absolute values derived for the mass are dependent on the shower model and on the range of distance from the shower core selected. Thus the method has uncovered further deficiencies in our understanding of shower modelling that must be resolved before the mass composition can be inferred from (sec θ)max.
Najdeno v: ključnih besedah
Ključne besede: Pierre Auger Observatory, Surface Detector, risetime of detector signal, azimuthal asymmetry, extensive air showers
Objavljeno: 03.03.2016; Ogledov: 2034; Prenosov: 114
.pdf Polno besedilo (243,04 KB)

2.
Solar Cycle Modulation of Cosmic Rays Observed with the Low Energy Modes of the Pierre Auger Observatory
Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Jimmy Masías-Meza, 2015, objavljeni znanstveni prispevek na konferenci

Opis: The low energy modes of the surface detector array of the Pierre Auger Observatory record variations in the flux of low energy secondary particles with extreme detail. These two modes consist of recording (1) the rate of signals for energies between ∼15 MeV and ∼100 MeV (the Scaler mode) and (2) the calibration charge histograms of the individual pulses detected by each water-Cherenkov station, covering different energy channels up to ∼1 GeV (the Histogram mode). Previous work has studied the flux of galactic cosmic rays on short and intermediate time scales (i.e. from minutes to weeks) using these low energy modes. In this work, after including a long- term correction to the response of the detectors, we present the first long-term analysis of the flux of cosmic rays using scalers and two energy bands of the calibration histograms. We show its sensitivity to the solar cycle variation and its relation to the solar modulation of cosmic rays for an 8-year period.
Najdeno v: ključnih besedah
Povzetek najdenega: ...The low energy modes of the surface detector array of the Pierre Auger Observatory record variations...
Ključne besede: Pierre Auger Observatory, Surface Detector, secondary cosmic rays, scaler mode, charge histogram mode, solar cycle modulation
Objavljeno: 03.03.2016; Ogledov: 2021; Prenosov: 127
.pdf Polno besedilo (533,18 KB)

3.
Studies in the atmospheric monitoring at the Pierre Auger Observatory using the upgraded Central Laser Facility
Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Carlos Medina-Hernandez, 2015, objavljeni znanstveni prispevek na konferenci

Opis: The Fluorescence Detector (FD) at the Pierre Auger Observatory measures the intensity of the scattered light from laser tracks generated by the Central Laser Facility (CLF) and the eXtreme Laser Facility (XLF) to monitor and estimate the vertical aerosol optical depth (τ(z,t)). This measurement is needed to obtain unbiased and reliable FD measurements of the arrival direction and energy of the primary cosmic ray, and the depth of the maximum shower development. The CLF was upgraded substantially in 2013 with the addition of a solid state laser, new generation GPS, a robotic beam calibration system, better thermal and dust isolation, and improved software. The upgrade also included a back-scatter Raman LIDAR to measure τ(z,t). The new features and applications of the upgraded instrument are described. These include the laser energy calibration and the atmospheric monitoring measurements. The first τ(z,t) results and comparisons after the upgrade are presented using different methods. The first method compares the FD hourly response to the scattered light from the CLF (or XLF) against a reference hourly profile measured during a clear night where zero aerosol contents are assumed. The second method simulates FD responses with different atmospheric parameters and selects the parameters that provide the best fit to the actual FD response. A third method uses the new Raman LIDAR receiver in-situ to measure the back-scatter light from the CLF laser. The results show a good data agreement for the first and second methods using FD stations located at the same distance from the facilities. Preliminary results of τ(z,t) using the Raman LIDAR are presented as well.
Najdeno v: ključnih besedah
Povzetek najdenega: ...The Fluorescence Detector (FD) at the Pierre Auger Observatory measures the...
Ključne besede: Pierre Auger Observatory, extensive air showers, the Fluorescence Detector, atmospheric monitoring, vertical aerosol optical depth, the Central Laser Facility, the eXtreme Laser Facility
Objavljeno: 03.03.2016; Ogledov: 1946; Prenosov: 113
.pdf Polno besedilo (3,96 MB)

4.
Measurement of the water-Cherenkov detector response to inclined muons using an RPC hodoscope
Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Pedro Assis, 2015, objavljeni znanstveni prispevek na konferenci

Opis: The Pierre Auger Observatory operates a hybrid detector composed of a Fluorescence Detector and a Surface Detector array. Water-Cherenkov detectors (WCD) are the building blocks of the array and as such play a key role in the detection of secondary particles at the ground. A good knowledge of the detector response is of paramount importance to lower systematic uncertainties and thus to increase the capability of the experiment in determining the muon content of the extensive air showers with a higher precision. In this work we report on a detailed study of the detector response to single muons as a function of their trajectories in the WCD. A dedicated Resistive Plate Chambers (RPC) hodoscope was built and installed around one of the detectors. The hodoscope is formed by two stand-alone low gas flux segmented RPC detectors with the test water-Cherenkov detector placed in between. The segmentation of the RPC detectors is of the order of 10 cm. The hodoscope is used to trigger and select single muon events in different geometries. The signal recorded in the water-Cherenkov detector and performance estimators were studied as a function of the trajectories of the muons and compared with a dedicated simulation. An agreement at the percent level was found, showing that the simulation correctly describes the tank response.
Najdeno v: ključnih besedah
Ključne besede: Pierre Auger Observatory, Water-Cherenkov detectors, detector calibration, inclined cosmic ray muons, Resistive Plate Chambers (RPC) hodoscope
Objavljeno: 03.03.2016; Ogledov: 2050; Prenosov: 123
.pdf Polno besedilo (1,27 MB)

5.
Automated procedures for the Fluorescence Detector calibration at the Pierre Auger Observatory
Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Gaetano Salina, 2015, objavljeni znanstveni prispevek na konferenci

Opis: The quality of the physics results, derived from the analysis of the data collected at the Pierre Auger Observatory depends heavily on the calibration and monitoring of the components of the detectors. It is crucial to maintain a database containing complete information on the absolute calibration of all photomultipliers and their time evolution. The low rate of the physics events implies that the analysis will have to be made over a long period of operation. This requirement imposes a very organized and reliable data storage and data management strategy, in order to guarantee correct data preservation and high data quality. The Fluorescence Detector (FD) consists of 27 telescopes with about 12,000 phototubes which have to be calibrated periodically. A special absolute calibration system is used. It is based on a calibrated light source with a diffusive screen, uniformly illuminating photomultipliers of the camera. This absolute calibration is performed every few years, as its use is not compatible with the operation of the detector. To monitor the stability and the time behavior, another light source system operates every night of data taking. This relative calibration procedure yields more than 2×10[sup]4 raw files each year, about 1 TByte/year. In this paper we describe a new web-interfaced database architecture to manage, store, produce and analyse FD calibration data. It contains the configuration and operating parameters of the detectors at each instant and other relevant functional parameters that are needed for the analysis or to monitor possible instabilities, used for the early discovery of malfunctioning components. Based on over 10 years of operation, we present results on the long term performance of FD and its dependence on environmental variables. We also report on a check of the absolute calibration values by analysing the signals left by stars traversing the FD field of view.
Najdeno v: ključnih besedah
Ključne besede: Pierre Auger Observatory, Fluorescence Detector, detector calibration and monitoring, automated calibration procedure
Objavljeno: 03.03.2016; Ogledov: 1666; Prenosov: 127
.pdf Polno besedilo (1,06 MB)

6.
Status and Prospects of the Auger Engineering Radio Array
Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Johannes Schulz, 2015, objavljeni znanstveni prispevek na konferenci

Opis: The Auger Engineering Radio Array (AERA) is an extension of the Pierre Auger Observatory. It is used to detect radio emission from extensive air showers in the 30 - 80 MHz frequency band. A focus of interest is the dependence of the radio emission on shower parameters such as the energy and the atmospheric depth of the shower maximum. After three phases of deployment, AERA now consists of 153 autonomous radio stations with different spacings, covering an area of about 17 km2. The size, station spacings, and geographic location at the same site or near other Auger extensions, are all targeted at cosmic ray energies above 10[sup]17 eV. The array allows us to explore different technical schemes to measure the radio emission as well as to cross calibrate our measurements with the established baseline detectors of the Auger Observatory. We present the most recent technological developments and selected experimental results obtained with AERA.
Najdeno v: ključnih besedah
Povzetek najdenega: ...Radio Array (AERA), radio emission from extensive air showers, detector cross-calibration...
Ključne besede: Pierre Auger Observatory, the Auger Engineering Radio Array (AERA), radio emission from extensive air showers, detector cross-calibration
Objavljeno: 03.03.2016; Ogledov: 1986; Prenosov: 112
.pdf Polno besedilo (2,79 MB)

7.
Improved limits to point-like sources of ultrahigh energy neutrinos with the Pierre Auger Observatory
Lili Yang, Marta Trini, Pablo Pieroni, Jaime Alvarez-Muniz, 2016, elaborat, predštudija, študija

Najdeno v: ključnih besedah
Ključne besede: ultrahigh energy neutrinos, Pierre Auger Observatory, surface detector
Objavljeno: 07.04.2016; Ogledov: 2086; Prenosov: 0
.pdf Polno besedilo (307,54 KB)

8.
Azimuthal asymmetry in the risetime of the surface detector signals of the Pierre Auger Observatory
Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, A. Aab, 2016, izvirni znanstveni članek

Opis: The azimuthal asymmetry in the risetime of signals in Auger surface detector stations is a source of information on shower development. The azimuthal asymmetry is due to a combination of the longitudinal evolution of the shower and geometrical effects related to the angles of incidence of the particles into the detectors. The magnitude of the effect depends upon the zenith angle and state of development of the shower and thus provides a novel observable, (secθ)max, sensitive to the mass composition of cosmic rays above 3×1018  eV. By comparing measurements with predictions from shower simulations, we find for both of our adopted models of hadronic physics (QGSJETII-04 and EPOS-LHC) an indication that the mean cosmic-ray mass increases slowly with energy, as has been inferred from other studies. However, the mass estimates are dependent on the shower model and on the range of distance from the shower core selected. Thus the method has uncovered further deficiencies in our understanding of shower modeling that must be resolved before the mass composition can be inferred from (secθ)max.
Najdeno v: ključnih besedah
Ključne besede: ultra-high energy cosmic rays (UHECR), UHECR mass composition, Pierre Auger Observatory, extensive air showers, Auger Surface Detector signals risetime, azimuthal symmetry
Objavljeno: 15.04.2016; Ogledov: 2400; Prenosov: 0
.pdf Polno besedilo (698,19 KB)

9.
Revealing local failed supernovae with neutrino telescopes
Lili Yang, Cecilia Lunardini, 2011, izvirni znanstveni članek

Najdeno v: ključnih besedah
Povzetek najdenega: ...neutrinos, failed supernova, Mt water detector, ...
Ključne besede: neutrinos, failed supernova, Mt water detector
Objavljeno: 09.05.2017; Ogledov: 1627; Prenosov: 89
URL Polno besedilo (0,00 KB)

10.
ASSESSMENT OF EFFECTIVE DOSES BASED ON VARIOUS RADON MEASURING TECHNIQUES
Nataša Smrekar, 2016, magistrsko delo

Opis: In my master's thesis, I have focused on radon gas in 43 buildings used for different purposes (23 schools, 3 kindergartens, 16 offices and a residential house) in which preliminary measurements had shown higher concentrations of radon gas. I carried out measurements of radon and short-lived radon products whilst simultaneously employing different measurement techniques. In all 43 buildings, I measured the instantaneous concentration of radon by using scintillation cells; in 18 buildings, I additionally measured the average concentration of radon by using solid state nuclear track detectors and in 10 buildings, I measured concentration retrospectively with solid state nuclear track detectors. In four selected buildings (a school, a kindergarten, an office and a residential house), I carried out the measurements by using all of the available equipment. I monitored the daily fluctuations of concentration of radon and short-lived radon products by using continuous monitors in 14 buildings. This is how I obtained the factor of radioactive equilibrium between radon and its short-lived products. Based on the results obtained, I calculated the effective doses. As the basis for calculating the doses, I used the instantaneous and average concentrations of radon and the equilibrium factor taken from literature (0.40) or own measurements. I compared the doses and critically evaluated them. In contrast to the previous research, I researched radon exclusively in areas with increased risk for radon. I studied the influence of the working regime on the concentration of radon in different working environments (i.e. a school, a kindergarten and an office).
Najdeno v: ključnih besedah
Povzetek najdenega: ...measurement technique, scintillation cell, solid-state nuclear track detector, retrospective detector, equilibrium factor, effective dose, comparison....
Ključne besede: Radon, short-lived radon products, measurement technique, scintillation cell, solid-state nuclear track detector, retrospective detector, equilibrium factor, effective dose, comparison.
Objavljeno: 28.09.2016; Ogledov: 2815; Prenosov: 200
.pdf Polno besedilo (1,86 MB)

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