Detection Of Extensive Air Showers Research Articles

The measurement of the cosmic ray primary energy spectrum at 10 16–10 18 eV with the KASCADE-Grande experiment

The KASCADE-Grande experiment operates at Karlsruhe Institute of Technology (KIT) in Germany. Itʼs aim is the study of the primary cosmic radiation, through Extensive Air Shower detection, in the range 1016–1018 eV. Here, measurements are of main interest to understand the high energy evolution of cosmic radiation: a change in the slope of the heavy primary spectrum is expected (as measured at lower energies for lighter primaries) as a possible confirmation of the predicted astrophysical mechanisms; moreover, in this range the transition from galactic to extragalactic radiation is supposed to take place and the observations could clarify the features of this transition, putting the basis for the interpretation of the data at the highest energies. For these tasks KASCADE-Grande fulfills very well the requirements, both concerning the acceptance and the experimental performances. The experiment is constituted by two co-operating arrays of detectors: the KASCADE array, with its 252 detectors in a dense grid of 200×200 m2 and the Grande array, made of 37 detectors arranged on a wider area of 700×700 m2. The Grande array samples the total charged particles size of the air shower, while the KASCADE array provides the muon size In this contribution, KASCADE-Grande measurement of the cosmic ray primary energy spectrum is presented. The exploited technique, calibrated with simulations, combines the charged particles component and muon component on a shower by shower basis, performing the energy estimation of each primary event. Other techniques are also performed, for a better evaluation of systematics and a check of consistency of the hadronic interaction model used in simulations.

CZELTA: An overview of the CZECH large-area time coincidence array

Main goal of the project CZELTA (CZEch Large- area Time coincidence Array) is to study global properties of high-energetic cosmic rays. To present date, project con- sists of 5 stations covering large area in the Czech republic capable of detection of extensive air showers with energy ex- ceeding 10 14 eV. Such a network of distant stations can be an ideal tool for probing global structure of cosmic rays. We present the design of the detection system and obtained re- sults.

First detection of extensive air showers by the TREND self-triggering radio experiment

An antenna array devoted to the autonomous radio-detection of high energy cosmic rays is being deployed on the site of the 21 cm array radio telescope in XinJiang, China. Thanks in particular to the very good electromagnetic environment of this remote experimental site, self-triggering on extensive air showers induced by cosmic rays has been achieved with a small scale prototype of the foreseen antenna array. We give here a detailed description of the detector and present the first detection of extensive air showers with this prototype.

Synchronous detection of extensive air showers by a HELYCON detector array and a deep sea underwater neutrino telescope: Statistical and systematiceffects

Extensive atmospheric showers observed in coincidence by an underwater neutrino telescope and a HELYCON (HEllenic LYceum Cosmic Observatories Network) floating scintillation array, offer an efficient calibration tool for the angular offset and the absolute position of a deep sea neutrino Cherenkov telescope. We report results of our studies concerning systematic effects and the calibration potential of the proposed techniques in various ν -telescope configurations and detector deployment depths.

Calibration and optimization of a very large volume neutrino telescope using extensive air showers

We report on a simulation study of the calibration potential offered by floating Extensive Air Shower (EAS) detector stations (HELYCON), operating in coincidence with the KM3NeT Mediterranean deep-sea neutrino telescope. We describe strategies in order to investigate for possible systematic errors in reconstructing the direction of energetic muons as well as to determine the absolute position of the underwater detector.

Results from the ARGO-YBJ experiment

The full coverage extensive air shower detector ARGO-YBJ, located in Tibet at 4300 m of altitude, has monitored the sky at gamma ray energy E > 0.6 TeV in the declination band from −10° to +70°. In 424 days the Crab Nebula and Mrk421 have been detected with a significance, respectively, of 7.0 and 8.0 standard deviations. The analysis of the cosmic ray background in the same sky band, has revealed the existence of a significant excess of the cosmic ray flux in two localized regions of angular size 10°–30°, confirming previous indications. The origin of such excesses is still unexplained. Concerning the gamma ray sources, the measured spectrum of the Crab Nebula is d N / d E = ( 3.7 ± 0.8 ) × 10 − 11 E − 2.67 ± 0.25 photons cm − 2 s − 1 TeV − 1 , in agreement with other experiments. During 2008 the observed Mrk421 flux was highly variable, with the strongest flares in March–June, in good correlation with X-ray data. One of the most intense flares occurred in the first half of June and has been deeply studied by different detectors in the energy range from optical to 100 MeV gamma rays, but only partially up to TeV energies, since the moonlight hampered the Cherenkov telescope measurements during the second and most intense part of the emission. Our data complete these observations, with the detection of a signal of intensity of about 7 Crab units on June 11–13, with a statistical significance of 4.2 standard deviations. The observed flux is consistent with a prediction made in the framework of the Synchrotron Self-Compton model, in which the flare is caused by a rapid acceleration of leptons in the jet.

The KASCADE-Grande experiment

KASCADE-Grande is the enlargement of the KASCADE extensive air shower detector, realized to expand the cosmic ray studies from the previous 10 14–10 17 eV primary energy range to 10 18 eV. This is performed by extending the area covered by the KASCADE electromagnetic array from 200×200 to 700×700 m 2 by means of 37 scintillator detector stations of 10 m 2 area each. This new array is named Grande and provides measurements of the all-charged particle component of extensive air showers ( N ch ), while the original KASCADE array particularly provides information on the muon content ( N μ ) . Additional dense compact detector set-ups being sensitive to energetic hadrons and muons are used for data consistency checks and calibration purposes. The performance of the Grande array and its integration into the entire experimental complex is discussed. It is demonstrated that the overall observable resolutions are adequate to meet the physical requirements of the measurements, i.e. primary energy spectrum and elemental composition studies in the primary cosmic ray energy range of 10 16–10 18 eV.

Full simulation of space-based extensive air showers detectors with ESAF

Future detection of extensive air showers (EAS) produced by ultra high energy cosmic particles by means of space-based fluorescence telescopes will open a new window on the universe and allow cosmic ray and neutrino astronomy at a level that is virtually impossible for ground based detectors. In the context of the extreme universe space observatory (EUSO) project, an end-to-end simulation of EAS observation with a spatial detector has been designed (EUSO simulation and analysis framework, ESAF). This paper describes the detailed Monte-Carlo developed to simulate all the physical processes involved in the fluorescence detection technique, from the EAS development to the instrument response. Particular emphasis is given to modeling the light propagation in the atmosphere and the effect of clouds. The simulation is used to assess the performances of EAS spatial detection. Main results on energy threshold and resolution, direction resolution and X max determination are reported. Results are based on EUSO telescope design, but are also extended to larger and more sensitive detectors.

Gamma-ray astronomy with the ARGO-YBJ experiment

The ARGO-YBJ experiment is an Extensive Air Shower detector which combines high altitude location (Tibet, People's Republic of China, 4300 m a.s.l.) and full coverage with Resistive Plate Counters, resulting in an energy threshold of a few hundred GeV. The large field of view (~2 sr) and high duty cycle allow the continuous monitoring of the Northern sky, searching for unknown sources and unpredictable events, such as flares in blazar emissions or high energy Gamma Ray Bursts. In this paper I will present some results obtained in γ-ray astronomy with the ARGO-YBJ experiment.

The IGY and beyond: A brief history of ground-based cosmic-ray detectors

The state of art of ground-based cosmic-ray research from its discovery to present is reviewed. After discovery of cosmic rays by Hess in 1912, the nature of the primary and secondary radiation was established from recordings by a variety of instruments, sensitive to various components of cosmic rays and operated at different latitudes, longitudes and altitudes, including instruments carried by balloons. The IGY formalized international co-operation and coordinated study of cosmic rays, which is vital for meaningful interpretation of cosmic-ray data. Data collected at different geographic locations require an effective cutoff rigidity as a data ordering parameter. This parameter is obtained from tracing trajectories of primary cosmic rays in the Earth’s magnetic field. After 50 years the world’s neutron monitor network remains still the backbone for studying intensity variations of primary cosmic rays in the rigidity ranges between 1 and 15 GV, associated with transport and with transient events. Also the penetrating muon and neutrino components of secondary cosmic rays have a long history of recording and fundamental problem investigations. Valuable data about composition and spectrum of primary cosmic rays in ever increasing high-energy regions have been obtained during the years of investigations with various configurations and types of extensive air shower detectors. The culture of personal involvement of the physicist in carrying out experiments and data acquisition characterized the continued vitality of cosmic-ray investigations ranging from its atmospheric, geomagnetic and heliospheric transport through to its solar and astrophysical origins.

Radio in Auger-offline

The Pierre Auger Collaboration started an R&D task force to investigate the extension of the Observatory with a self-triggering antenna array for the detection of extensive air showers by their radio-signals. First signals measured with test-set-ups require establishing an environment for the analysis of data and simulations. Extending the general offline software framework developed within Auger for radio-detection offers many short-term as well as long-term benefits.

Time over threshold electronics for an underwater neutrino telescope

The use of time over threshold (ToT) digitization techniques for the treatment of the output signal of the PMTs of the KM3NeT detector is under consideration by the KM3NeT collaboration. In this technique the leading and trailing edge of the signal above a certain threshold are time stamped and the corresponding times are sent to the onshore acquisition system. More information can be obtained by applying the same scheme at multiple threshold levels. In this note, we present the efficiency of such a digitization technique applied to signals provided by the HEllenic LYceum Cosmic Observatories Network (HELYCON) extensive air shower detector. The hardware used has been designed by the Hellenic Open University (HOU) group and it is based on a high precision time to digital converter (HPTDC) chip developed at CERN and offering up to 32 channels with a digitization accuracy of 100 ps. We describe the operation and performance of this electronics and we evaluate the reconstruction accuracy of PMT signals using data collected from Extensive Air Showers. Finally, we report on our plans to use this electronics on Optical Modules proposed to be used in KM3NeT.

Spectrally resolved pressure dependence measurements of air fluorescence emission with AIRFLY

The knowledge of the fluorescence emission as a function of atmospheric parameters is essential for the detection of extensive air showers with the fluorescence technique. In this paper, we summarize AIRFLY published measurements of the pressure dependence of the fluorescence yield. The spectral distribution of the fluorescent light between 280 and 429 nm has been measured with high resolution. Relative intensities of 34 spectral lines have been determined. The pressure dependence of 25 lines was measured in terms of quenching reference pressures p λ ′ in air. This set of AIRFLY measurements yields the most comprehensive parametrization of the pressure dependence of the fluorescent spectrum.

Use of floating surface detector stations for the calibration of a deep-sea neutrino telescope

We propose the operation of floating Extensive Air Shower (EAS) detector stations in coincidence with the KM3NeT Mediterranean deep-sea neutrino telescope to determine the absolute position and orientation of the underwater detector and to investigate possible systematic angular errors. We evaluate the accuracy of the proposed calibration strategies using a detailed simulation of the EAS and KM3NeT detectors.

Air shower radio detection with LOPES

LOPES is an array of 30 radio antenna co-located with the KASCADE-Grande extensive air shower detector in Karlsruhe, Germany. It is designed as a digital radio interferometer for the detection of radio emission from extensive air showers. LOPES features high bandwidth and fast data processing. A unique asset is the concurrent operation with KASCADE-Grande. We report about the progress in understanding the radio signals measured by LOPES. In addition, the status and further perspectives of LOPES and the large scale application of this novel detection technique are sketched.

Ground detectors for the study of cosmic ray showers

We describe the work that we have done over the last decade to design and construct instruments to measure properties of cosmic rays in Mexico. We describe the detection of decaying and crossing muons in a water Cherenkov detector and discuss an application of these results to calibrate water Cherenkov detectors. We also describe a technique to separate isolated isolated muons and electrons in water Cherenkov detector. Next we describe the design and performance of a hybrid extensive air shower detector array built on the Campus of the University of Puebla (19°N, 90°W, 800 g/cm2) to measure the energy, arrival direction and composition of primary cosmic rays with energies around 1 PeV.

The neutron ‘thunder’ accompanying the extensive air shower

Simulations show that neutrons are the most abundant component among extensive air shower (EAS) hadrons. However, multiple neutrons which appear with long delays in neutron monitors nearby the EAS core (neutron thunder) are mostly not the neutrons of the shower, but have a secondary origin. The bulk of them is produced by high energy EAS hadrons hitting the monitors. The delays are due to the thermalization and diffusion of neutrons in the moderator and reflector of the monitor accompanied by the production of secondary gamma quanta. This conclusion raises the important problem of the interaction of EAS with the ground, the stuff of the detectors and their environment since they have often hydrogen-containing materials like polyethilene in neutron monitors. Such interaction can give an additional contribution to the signal in the EAS detectors. It can be particularly important for the signals from scintillator or water tank detectors at kilometre-long distances from the EAS core, where neutrons of the shower become the dominant component after a few microseconds behind the EAS front.

Performance of the resistive plate chambers in the ARGO-YBJ experiment

The ARGO-YBJ experiment is designed for the detection of Extensive Air Showers (EAS) in the primary energy range 100 GeV–10 TeV. Its full-coverage feature allows to lower the energy threshold about one order of magnitude with respect to sampling EAS detectors. Here the performance of the RPC array is described and the current status of the experiment is presented.

The Roland Maze Project – school-based extensive air shower network

We plan to construct the large area network of extensive air shower detectors placed on the roofs of high school buildings in the city of Łodź. Detection points will be connected by INTERNET to the central server and their work will be synchronized by GPS. The main scientific goal of the project are studies of ultra high energy cosmic rays. Using existing town infrastructure (INTERNET, power supply, etc.) will significantly reduce the cost of the experiment. Engaging high school students in the research program should significantly increase their knowledge of science and modern technologies, and can be a very efficient way of science popularisation. We performed simulations of the projected network capabilities of registering Extensive Air Showers and reconstructing energies of primary particles. Results of the simulations and the current status of project realisation will be presented.

THE ROLAND MAZE PROJECT — COSMIC RAY REGISTRATION AT SCHOOLS

Experimental studies of cosmic rays at the highest energies (above 1018 eV) are the main scientific goal of the projected large area network of extensive air shower detectors. Placing the detectors on the roofs of high school buildings will lower the cost by using the existing urban infrastructure (INTERNET, power supply, etc.), and can be a very efficient way of science popularisation by engaging high school students in the research program. 30 high schools in Łódź are already involved in the project. The project has recently obtained some financial support from the City Council of Łódź. The donation enabled us to start experimental work on detector construction details. A cycle of lectures and seminars devoted to different aspects of project realization (detector construction, on-line data acquisition system, C++ programming) has been organized for students at our Institute and at schools.