79 research outputs found
The Atmospheric Monitoring System of the JEM-EUSO Space Mission
An Atmospheric Monitoring System (AMS) is a mandatory and key device of a
space-based mission which aims to detect Ultra-High Energy Cosmic Rays (UHECR)
and Extremely-High Energy Cosmic Rays (EHECR) from Space. JEM-EUSO has a
dedicated atmospheric monitoring system that plays a fundamental role in our
understanding of the atmospheric conditions in the Field of View (FoV) of the
telescope. Our AMS consists of a very challenging space infrared camera and a
LIDAR device, that are being fully designed with space qualification to fulfil
the scientific requirements of this space mission. The AMS will provide
information of the cloud cover in the FoV of JEM-EUSO, as well as measurements
of the cloud top altitudes with an accuracy of 500 m and the optical depth
profile of the atmosphere transmittance in the direction of each air shower
with an accuracy of 0.15 degree and a resolution of 500 m. This will ensure
that the energy of the primary UHECR and the depth of maximum development of
the EAS ( Extensive Air Shower) are measured with an accuracy better than 30\%
primary energy and 120 depth of maximum development for EAS occurring
either in clear sky or with the EAS depth of maximum development above
optically thick cloud layers. Moreover a very novel radiometric retrieval
technique considering the LIDAR shots as calibration points, that seems to be
the most promising retrieval algorithm is under development to infer the Cloud
Top Height (CTH) of all kind of clouds, thick and thin clouds in the FoV of the
JEM-EUSO space telescope
Thin and thick cloud top height retrieval algorithm with the Infrared Camera and LIDAR of the JEM-EUSO Space Mission
The origin of cosmic rays have remained a mistery for more than a century.
JEM-EUSO is a pioneer space-based telescope that will be located at the
International Space Station (ISS) and its aim is to detect Ultra High Energy
Cosmic Rays (UHECR) and Extremely High Energy Cosmic Rays (EHECR) by observing
the atmosphere. Unlike ground-based telescopes, JEM-EUSO will observe from
upwards, and therefore, for a properly UHECR reconstruction under cloudy
conditions, a key element of JEM-EUSO is an Atmospheric Monitoring System
(AMS). This AMS consists of a space qualified bi-spectral Infrared Camera, that
will provide the cloud coverage and cloud top height in the JEM-EUSO Field of
View (FoV) and a LIDAR, that will measure the atmospheric optical depth in the
direction it has been shot. In this paper we will explain the effects of clouds
for the determination of the UHECR arrival direction. Moreover, since the cloud
top height retrieval is crucial to analyze the UHECR and EHECR events under
cloudy conditions, the retrieval algorithm that fulfills the technical
requierements of the Infrared Camera of JEM-EUSO to reconstruct the cloud top
height is presently reported.Comment: 5 pages, 6 figures, Atmohead Conference 201
A new composition-sensitive parameter for Ultra-High Energy Cosmic Rays
A new family of parameters intended for composition studies in cosmic ray
surface array detectors is proposed. The application of this technique to
different array layout designs has been analyzed. The parameters make exclusive
use of surface data combining the information from the total signal at each
triggered detector and the array geometry. They are sensitive to the combined
effects of the different muon and electromagnetic components on the lateral
distribution function of proton and iron initiated showers at any given primary
energy. Analytical and numerical studies have been performed in order to assess
the reliability, stability and optimization of these parameters. Experimental
uncertainties, the underestimation of the muon component in the shower
simulation codes, intrinsic fluctuations and reconstruction errors are
considered and discussed in a quantitative way. The potential discrimination
power of these parameters, under realistic experimental conditions, is compared
on a simplified, albeit quantitative way, with that expected from other surface
and fluorescence estimators.Comment: 27 pages, 17 figures. Submitted to a refereed journa
Obtaining cloud top height from WRF model vertical profiles: application to the EUSO program
The objective of the Extreme Universe Space Observatory (EUSO) program is detection and measurement of high-energy particles that reach earth?s atmosphere from space. Clouds at mid and upper levels of the troposphere can interfere with such detection. Therefore, determining cloud top height with high accuracy is crucial to estimating the effect of clouds on these measurements.With this aim, we developed a method to extract that height using cloud temperature via vertical profiles predicted by the WRF model
The Spanish Infrared Camera onboard the EUSO-BALLOON (CNES) flight on August 24, 2014
The EUSO-Balloon (CNES) campaign was held during Summer 2014 with a launch on August
24. In the gondola, next to the Photo Detector Module (PDM), a completely isolated Infrared
camera was allocated. Also, a helicopter which shooted flashers flew below the balloon. We have
retrieved the Cloud Top Height (CTH) with the IR camera, and also the optical depth of the nonclear atmosphere have been inferred with two approaches: The first one is with the comparison of the brightness temperature of the cloud and the real temperature obtained after the pertinent
corrections. The second one is by measuring the detected signal from the helicopter flashers by the IR Camera, considering the energy of the flashers and the location of the helicopter
The atmospheric science of JEM-EUSO
An Atmospheric Monitoring System (AMS) is critical suite of instruments for JEM-EUSO whose aim is to detect Ultra-High Energy Cosmic Rays (UHECR) and (EHECR) from Space. The AMS
comprises an advanced space qualified infrared camera and a LIDAR with cross checks provided by a ground-based and airborne Global Light System Stations. Moreover the Slow Data Mode of JEM-EUSO has been proven crucial for the UV background analysis by comparing the UV and IR images. It will also contribute to the investigation of atmospheric effects seen in the data from the GLS or even to our understanding of Space Weather
The Fluorescence Detector of the Pierre Auger Observatory
The Pierre Auger Observatory is a hybrid detector for ultra-high energy
cosmic rays. It combines a surface array to measure secondary particles at
ground level together with a fluorescence detector to measure the development
of air showers in the atmosphere above the array. The fluorescence detector
comprises 24 large telescopes specialized for measuring the nitrogen
fluorescence caused by charged particles of cosmic ray air showers. In this
paper we describe the components of the fluorescence detector including its
optical system, the design of the camera, the electronics, and the systems for
relative and absolute calibration. We also discuss the operation and the
monitoring of the detector. Finally, we evaluate the detector performance and
precision of shower reconstructions.Comment: 53 pages. Submitted to Nuclear Instruments and Methods in Physics
Research Section
Atmospheric effects on extensive air showers observed with the Surface Detector of the Pierre Auger Observatory
Atmospheric parameters, such as pressure (P), temperature (T) and density,
affect the development of extensive air showers initiated by energetic cosmic
rays. We have studied the impact of atmospheric variations on extensive air
showers by means of the surface detector of the Pierre Auger Observatory. The
rate of events shows a ~10% seasonal modulation and ~2% diurnal one. We find
that the observed behaviour is explained by a model including the effects
associated with the variations of pressure and density. The former affects the
longitudinal development of air showers while the latter influences the Moliere
radius and hence the lateral distribution of the shower particles. The model is
validated with full simulations of extensive air showers using atmospheric
profiles measured at the site of the Pierre Auger Observatory.Comment: 24 pages, 9 figures, accepted for publication in Astroparticle
Physic
Anisotropy studies around the galactic centre at EeV energies with the Auger Observatory
Data from the Pierre Auger Observatory are analyzed to search for
anisotropies near the direction of the Galactic Centre at EeV energies. The
exposure of the surface array in this part of the sky is already significantly
larger than that of the fore-runner experiments. Our results do not support
previous findings of localized excesses in the AGASA and SUGAR data. We set an
upper bound on a point-like flux of cosmic rays arriving from the Galactic
Centre which excludes several scenarios predicting sources of EeV neutrons from
Sagittarius . Also the events detected simultaneously by the surface and
fluorescence detectors (the `hybrid' data set), which have better pointing
accuracy but are less numerous than those of the surface array alone, do not
show any significant localized excess from this direction.Comment: Matches published versio
The exposure of the hybrid detector of the Pierre Auger Observatory
The Pierre Auger Observatory is a detector for ultra-high energy cosmic rays.
It consists of a surface array to measure secondary particles at ground level
and a fluorescence detector to measure the development of air showers in the
atmosphere above the array. The "hybrid" detection mode combines the
information from the two subsystems. We describe the determination of the
hybrid exposure for events observed by the fluorescence telescopes in
coincidence with at least one water-Cherenkov detector of the surface array. A
detailed knowledge of the time dependence of the detection operations is
crucial for an accurate evaluation of the exposure. We discuss the relevance of
monitoring data collected during operations, such as the status of the
fluorescence detector, background light and atmospheric conditions, that are
used in both simulation and reconstruction.Comment: Paper accepted by Astroparticle Physic
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