1. Azimuthal asymmetry in the risetime of the Surface Detector signals of the Pierre Auger ObservatoryMarko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Ignacio Minaya, 2015, published scientific conference contribution Abstract: 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.
Found in: ključnih besedah
Keywords: Pierre Auger Observatory, Surface Detector, risetime of detector signal, azimuthal asymmetry, extensive air showers
Published: 03.03.2016; Views: 2151; Downloads: 119
 Fulltext (243,04 KB) |
2. Solar Cycle Modulation of Cosmic Rays Observed with the Low Energy Modes of the Pierre Auger ObservatoryMarko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Jimmy Masías-Meza, 2015, published scientific conference contribution Abstract: 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.
Found in: ključnih besedah
Summary of found: ...The low energy modes of the surface detector array of the
Pierre Auger Observatory record variations...
Keywords: Pierre Auger Observatory, Surface Detector, secondary cosmic rays, scaler mode, charge histogram mode, solar cycle modulation
Published: 03.03.2016; Views: 2139; Downloads: 132
Fulltext (533,18 KB) |
3. Studies in the atmospheric monitoring at the Pierre Auger Observatory using the upgraded Central Laser FacilityMarko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Carlos Medina-Hernandez, 2015, published scientific conference contribution Abstract: 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.
Found in: ključnih besedah
Summary of found: ...The Fluorescence Detector (FD) at the Pierre Auger Observatory
measures the...
Keywords: Pierre Auger Observatory, extensive air showers, the Fluorescence Detector, atmospheric monitoring, vertical aerosol optical depth, the Central Laser Facility, the eXtreme Laser Facility
Published: 03.03.2016; Views: 2099; Downloads: 117
Fulltext (3,96 MB) |
4. Measurement of the water-Cherenkov detector response to inclined muons using an RPC hodoscopeMarko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Pedro Assis, 2015, published scientific conference contribution Abstract: 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.
Found in: ključnih besedah
Keywords: Pierre Auger Observatory, Water-Cherenkov detectors, detector calibration, inclined cosmic ray muons, Resistive Plate Chambers (RPC) hodoscope
Published: 03.03.2016; Views: 2168; Downloads: 128
Fulltext (1,27 MB) |
5. Automated procedures for the Fluorescence Detector calibration at the Pierre Auger ObservatoryMarko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Gaetano Salina, 2015, published scientific conference contribution Abstract: 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.
Found in: ključnih besedah
Keywords: Pierre Auger Observatory, Fluorescence Detector, detector calibration and monitoring, automated calibration procedure
Published: 03.03.2016; Views: 1765; Downloads: 133
Fulltext (1,06 MB) |
6. Status and Prospects of the Auger Engineering Radio ArrayMarko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Johannes Schulz, 2015, published scientific conference contribution Abstract: 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.
Found in: ključnih besedah
Summary of found: ...Radio Array (AERA),
radio emission from extensive air showers,
detector cross-calibration...
Keywords: Pierre Auger Observatory, the Auger Engineering Radio Array (AERA), radio emission from extensive air showers, detector cross-calibration
Published: 03.03.2016; Views: 2089; Downloads: 116
Fulltext (2,79 MB) |
7. Improved limits to point-like sources of ultrahigh energy neutrinos with the Pierre Auger ObservatoryLili Yang, Marta Trini, Pablo Pieroni, Jaime Alvarez-Muniz, 2016, treatise, preliminary study, study Found in: ključnih besedah
Keywords: ultrahigh energy neutrinos, Pierre Auger Observatory, surface detector
Published: 07.04.2016; Views: 2224; Downloads: 0
Fulltext (307,54 KB) |
8. Azimuthal asymmetry in the risetime of the surface detector signals of the Pierre Auger ObservatoryMarko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, SAMO STANIČ, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, A. Aab, 2016, original scientific article Abstract: 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.
Found in: ključnih besedah
Keywords: ultra-high energy cosmic rays (UHECR), UHECR mass composition, Pierre Auger Observatory, extensive air showers, Auger Surface Detector signals risetime, azimuthal symmetry
Published: 15.04.2016; Views: 2546; Downloads: 0
Fulltext (698,19 KB) |
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10. ASSESSMENT OF EFFECTIVE DOSES BASED ON VARIOUS RADON MEASURING TECHNIQUESNataša Smrekar, 2016, master's thesis Abstract: 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).
Found in: ključnih besedah
Summary of found: ...measurement technique, scintillation cell, solid-state nuclear track detector, retrospective detector, equilibrium factor, effective dose, comparison....
Keywords: Radon, short-lived radon products, measurement technique, scintillation cell, solid-state nuclear track detector, retrospective detector, equilibrium factor, effective dose, comparison.
Published: 28.09.2016; Views: 2964; Downloads: 204
Fulltext (1,86 MB) |
