Extensive Air Shower Experiment Research Articles

Front-end readout boards for streamer tube muon tracking detector in the KASCADE EAS Experiment

A new design of a readout front-end board for large area streamer tube muon tracking detectors is presented. Such boards have proved to work well in the KASCADE extensive air shower experiment.

An eight-channel pulse-shape comparator to discriminate signals from fast scintillation detectors

An eight-channel pulse-shape comparator board is designed to discriminate the signals from fast scintillation detectors. Each channel of the comparator board has guaranteed output with maximum speed of 20 ns. The simple design and low cost per channel make it preferable for use in cosmic rays as well as in extensive air shower (EAS) experiments. A description of the environmental operation and test of the electronics is presented. This device is presently used in an EAS experiment, Gauhati University, Assam, India. We present here, details about the hardware aspect of the electronics. Results of the comparator electronics are also presented.

An integrated pulse-width trigger unit for triggering EAS events

An integrated pulse-width trigger unit is reported. The unit is developed in the Mini Array Research Laboratory, UHE Cosmic Ray Research, Gauhati University, Assam, India. The modest design and low cost make it favourable for the use in Extensive Air Shower experiments among small research groups. A description of the operation and tests of the unit is presented. This electronics is presently used in an EAS experiment, Gauhati University, Assam, India, to trigger the UHE Cosmic Ray events (Bezboruah et al., Astro. Part. Phys. 11(3) (1999) 395). We present here details about the hardware, test, calibration and results of the unit and the performances of the unit in the experiment.

The detector system for measurement of multiple cosmic muons in the central detector of KASCADE

A detector system for directional and time correlation measurements of multiple cosmic muons has been set up within the extensive air shower experiment KASCADE. The system consists of two layers (129 m 2 area each) of position-sensitive multiwire proportional chambers (MWPC) triggered by a layer of segmented plastic scintillation counters placed upon an iron/concrete shielding above the MWPCs. Operation conditions and performance of the MWPCs have been studied by means of a prototype arrangement consisting of a stack of four detectors and two trigger layers. Results of the detailed prototype studies are presented and discussed. In particular, it has been found that for the present purposes an operation with a commonly used argon–methane gas mixture instead of previously used argon–isobutane leads to an excellent performance. The chambers are integrated into the KASCADE experiment as described and are in continuous operation since 1996. Some typical measurements with the full detector assembly are used to illustrate which features of extensive air showers can be studied.

On Big Bang relics, the neutrino mass and the spectrum of cosmic rays

It is shown that high-energy features of the cosmic ray spectrum, in particular the kink around 4 PeV and the corresponding change in spectral index, may be explained from interactions between highly energetic cosmic protons and relic Big Bang antineutrinos, if the latter have a rest mass of about 0.4 eV/ c 2. This explanation is supported by experimental data from extensive air-shower experiments, and in particular by the observation (Fly's Eye) of a second kink around 300 PeV, and by the abrupt change in the chemical composition of the cosmic ray spectrum that occurs at that energy. Both facts follow naturally from our theory, which predicts additional verifiable features of the cosmic ray spectrum in the few-PeV region, e.g. an abrupt decrease in the p/ α ratio.

Estimation of the chemical composition in the “knee” region from the muon/electron ratio in EAS

New data on the muon/electron ratio derived from the KASCADE extensive air shower experiment are presented. This ratio is known to be the most sensitive parameter in the determination of the mass of the primary particle when using ground array data. The particle numbers are measured with the KASCADE array comprising 500 m 2 of e/γ- and 620 m 2 of μ - detectors. The primary mass is inferred on an event-by-event basis by comparing the experimental data to corresponding EAS simulations. We observe a change towards a heavier composition with increasing energy above the knee. The sensitivity of this result to the specific hadronic interaction model employed in the simulations (e.g. VENUS and QGSJET) is discussed.

Specific interactions at cosmic ray energies for extensive air shower experiments

The HIJING and VENUS models of relativistic hadron-nucleus and nucleus-nucleus collisions are used to study interactions of hadron-hadron, hadron-nitrogen and nucleus-nitrogen collisions, specific for the extensive air shower developments initiated by cosmic rays in the atmosphere. The transverse energy, transverse momenta and spectra of secondary particles as well as their energy and mass dependence have been investigated in detail. Results are presented with particular emphasis on the contributions of mini-jets in the HIJING model and the validity of superposition models in this energy range.

Comparison of the performance of various light enclosures for extensive air shower experiments

We have carried out a series of measurements with twenty-one light enclosures of different geometry and inside finishes to compare their performance for use in extensive air shower experiments. It is found that for light enclosures with white inside finish there is an inherent induced uncertainty in time measurement, in addition to the uncertainty arising from the uncertain transit location of the shower particle in a large area scintillator. Both of these uncertainties which can not be improved with better electronics limit the angular resolution of EAS arrays.

The KASCADE Experiment

A new extensive air shower (EAS) experiment has been installed at the site of the Forschungszentrum Karlsruhe. The main aim of the KASCADE [1] project is the determination of the chemical composition in the energy range around the knee of the primary cosmic ray spectrum. The main advantage of the new installation is the simultaneous measurement of a large number of observables for each individual event. This is achieved by the combination of various advanced detection techniques for the electromagnetic, the muonic, and the hadronic component of the extensive air showers. Data taking with a large part of the experiment has started at the end of 1995. The estimated accuracy of air shower data is discussed for the various detector components of KASCADE and first preliminary results are presented.

The Kascade experiment

A new extensive air shower (EAS) experiment has been installed at the laboratory site of the Forschungszentrum Karlsruhe. The main aim of the KASCADE [1] project is the determination of the chemical composition in the energy range around and above the knee of the primary cosmic ray spectrum. The main advantage of the new installation is the simultaneous measurement of a large number of observables for each individual event. This is achieved by the combination of various advanced detection techniques for the electromagnetic, the muonic, and the hadronic component of the extensive air showers. Data taking with a large part of the experiment has started at the end of 1995. The estimated accuracy of air shower data is discussed for the various detector components of KASCADE and first very preliminary results are presented.

The Formation of Galactic Cosmic Rays Spectrum

The cosmic ray spectrum can be formed in source by an acceleration process or by the effects of propagation in photons and magnetic fields of galactic and/or extragalactic space. The influence of magnetic field turbulence on the propagation of cosmic ray nuclei has been investigated. We have found that the regular component of galactic magnetic field should be equal to (0.35 μ G) but turbulent component have a mean strange value (4.65 μ G) for description whole feature observed in spectrum of cosmic rays. The propagation paths of nuclei in the galactic magnetic field are changed at the same energies where Extensive Air Shower (EAS) experiments observes alteration in the energy spectrum of cosmic ray. The ‘knee’ in the energy spectrum is due to two processes photo disintegration of nuclei in a soft photon field, type thermal bremsstrahlung with (kT=20) eV and leakage from Galaxy. A concave down among (2 ÷ 5 · 1018) eV observed in the energy spectrum is caused because above this energy the trajectories of protons are strike line in galactic magnetic field, so the propagation length is simple geometric path and do not depend from energy. The trajectories of iron are bending by magnetic field up to energy (1020) eV suffering the photo disintegration, so the secondary protons from destruction of heavy nuclei are isotropic. Only neutrons super high energy can provide some anisotropy. A good agreement with total cosmic ray spectrum can be obtained for parameters widely accepted for the galactic space. The model explain the data set, that the fraction of heavy nuclei increases up to (1016) eV. At energies (1016 ÷ 3 · 1018) eV the mixed mass compositions do not varies so much, but above this energy mass composition become lighter due to photo disintegration process of heavy nuclei. The secondary protons and spectra of light nuclei originating from the destruction of heavy nuclei have the maximum just above the ‘knee’. We suggest that secondary protons (PS) and nuclei of groups (He and CNO) make up the second component of cosmic ray spectrum proposed recently by Wdowczyk (1984), Wdowczyk and Wolfendale (1989), Fichtel and Linsley (1986), and discussed by Gaisser (1991). Verification of the proposed model by the observations of UHE neutrons and VHE/UHE gamma rays from point sources is possible.

Data acquisition and monitoring system for the UHE gamma ray experiment at Kolar Gold Fields

A computerised on-line data acquisition system has been implemented to acquire data and monitor all the detectors in an extensive air shower experiment at Kolar Gold Fields, India, designed to search for point sources of Ultra High Energy gamma rays. It is based on the LSI-11 microcomputer, which has a powerful instruction set and a daisy chained vectored interrupt facility. Two personal computers are linked with LSI-11 through a 16-bit communication bus, to transfer data for a quick analysis. While the system performs this function in the background, it can be interrupted, at different priority levels, by several foreground functions, such as event data acquisition, detector monitoring, etc. The hardware and software features of the data acquisition system are described in detail.

Large-P T physics with cosmic-ray events

Extensive Air Shower (EAS) experiments with high granularity have reported the detection of multicore events. On the other hand, multicluster and double-core events have been observed with emulsion chambers (EC) at mountain altitudes since the late '70s. A striking characteristic of these events is the large transverse momentum of the clusters. At accelerator energy region, it is known that jet production in deep inelastic hadronic processes is associated with the emission of large-P T particles. In this paper we analyse the possibility that both EAS and EC events represent the same physical process, discussing the physical consequences of this fact and the possibilities offered by both techniques in integrating the accelerators data.

The KASCADE cosmic ray experiment

KASCADE is an extensive air shower experiment under construction in the Karlsruhe Nuclear Research Centre. Its main aim is to measure primary cosmic ray composition above the range where direct measurements are possible. The experiment will register a larger number of observables for each individual shower than previous ones and should be able to distinguish at least three groups of primaries: the light elements (p, He), the C-N-O and the iron groups.

The trigger electronics for the array part of the KASCADE extensive air shower experiment

The trigger electronics for the array part of the KASCADE cosmic ray extensive air shower experiment is presented. The tasks performed by the trigger logic are described in detail. A brief review on the hardware implementation of the Trigger Unit is included.

Total inelasticity in p14N interactions at 103-104 TeV

A number of characteristics of groups of the highest energy particles in extensive air showers (so-called gamma h-families) measured in the cosmic ray Pamir experiment and the data from the Tian-Shan extensive air shower experiment were compared with those simulated using three different h14N interaction models distinguished mainly by the dependence of the total inelasticity on energy: namely increasing, constant and decreasing. The chemical composition of the primary cosmic rays varied from so-called normal to extremely enriched by heavy nuclei. The detection of gamma h-families in emulsion chambers was also simulated. On the basis of the comparison, we conclude that the total inelasticity in h14N interactions up to laboratory energy of 104 TeV is greater than 0.55, and that an energy-independent value of 0.55 is in contradiction with the data we consider at any cross-section which is consistent with the cosmic ray experimental data and for any composition of primary cosmic rays from so-called normal to super-heavy. The quark gluon string model with ktot increasing up to 0.84 at 104 TeV and the inelastic charge-exchange probability of 0.3-0.5 fits well the data used.

Afterpulses and decay times of fast scintillation counters for extensive air shower experiments

Abstract A fast scintillation counter system to observe the arrival time distribution of relativistic particles in extensive air showers has been developed. The generation rate of afterpulses observed by a ternary plastic scintillator counter of a fast-time-response photomultiplier were studied in detail. It was found that the effect of afterpulses generated in the photomultiplier and scintillation process was negligibly small compared with that of afterpulses produced by delayed particles in the shower. It was also found that long decay components in the scintillator output can be explained as being due to afterpulses.

Energy spectrum of primary cosmic rays above 1017.0 eV determined from extensive air shower experiments at Akeno

The energy spectrum of primary cosmic rays above 1017.0 eV has been updated from data collected with two extensive air shower arrays operating at Akeno, one with area 1 km2 and the other with area 20 km2. Along with the authors previous results in the lower energy region, the energy spectrum has been determined over about five decades of energy from 1014.5 eV to 1019.8 eV. A change in the index of the power-law energy spectrum is observed around 1017.8 eV, as well as the usual features, namely the knee around 1015.7 eV and the ankle around 1019.0 eV. The indices of the differential power-law energy spectrum are: (2.62+or-0.12) below 1015.7 eV, (3.02+or-0.03) for 1015.7 approximately 1017.8 eV and (3.16+or-0.08) for 1017.8 approximately 1018.8 eV. There is an indication of a flattening of the spectrum above approximately 1018.8 eV with an index of (2.8+or-0.3). The flux above 1018 eV is (1.5 approximately 2.4)*10-12 m-2s-1sr-1 and is in good agreement with other experiments. The number of showers above 1019.5 eV is seven for an exposure of 80 km2 yr sr and further investigation by a new Akeno giant air shower array (AGASA), whose operation has started, is necessary to determine a cutoff energy in the spectrum, if any.

The CYGNUS extensive air-shower experiment

The CYGNUS extensive air-shower experiment is described. The design criteria, construction and operation details, and performance characteristics are presented. A discussion of the data analysis techniques is given. Finally, several enhancements and improvements in the apparatus are described.

Extensive air shower experiment at Kolar Gold Fields

An experiment to determine the nature of primary cosmic rays of energy > 10 14 eV by studying high energy (> 220 GeV) muons and their correlations with other parameters of extensive air showers generated by them, was carried out at Kolar Gold Fields, India (atmospheric depth of 920 g cm −2). An accurate estimate of shower parameters in showers as small as 10 4 particles was achieved by means of a closely packed array of large area detectors and by employing special methods of analysis. In this paper, the details of the array, the data recording system, the procedure of data analysis and error estimates are described.