GRAPES-3—A high-density air shower array for studies on the structure in the cosmic-ray energy spectrum near the knee

Gupta, Sunil; Aikawa, Yuri; Gopalakrishnan, N. V.; Hayashi, Y.; Ikeda, N.; Ito, N.; Jain, Atul K.; John, A.; Karthikeyan, S.; Kawakami, S.; Matsuyama, T.; Mohanty, D. K.; Mohanty, P. K.; Morris, S. D.; Nonaka, T.; Oshima, A.; Rao, Balkrishna C.; Ravindran, K.; Sasano, M.; Sivaprasad, K.; Sreekantan, B. V.; Tanaka, Hidekazu; Tonwar, S. C.; Viswanathan, K. S.; Yoshikoshi, T.

doi:10.1016/j.nima.2004.11.025

Cited by 98 publications

(76 citation statements)

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“…Belov et al (2001) and Kane (2010) maintain that there is a reasonable correlation between the FD magnitude and the product of maximum magnetic field and maximum solar wind velocity. Dumbović et al (2012) also found reasonable correlation A&A 580, A41 (2015) detectors (each 1 m 2 ), with a distance of 8 m between adjacent detectors deployed in a hexagonal geometry (Gupta et al 2005;Mohanty et al 2009;Mohanty et al 2012). The GRAPES-3 array is designed to measure the energy spectrum and composition of the primary cosmic rays in the energy region from 10 TeV to 100 PeV (Gupta et al 2009;Tanaka et al 2012).…”

Section: Introductionmentioning

confidence: 83%

How are Forbush decreases related to interplanetary magnetic field enhancements?

Arunbabu

Antia

Dugad

et al. 2015

A&A

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Aims. A Forbush decrease (FD) is a transient decrease followed by a gradual recovery in the observed galactic cosmic ray intensity. We seek to understand the relationship between the FDs and near-Earth interplanetary magnetic field (IMF) enhancements associated with solar coronal mass ejections (CMEs). Methods. We used muon data at cutoff rigidities ranging from 14 to 24 GV from the GRAPES-3 tracking muon telescope to identify FD events. We selected those FD events that have a reasonably clean profile, and magnitude >0.25%. We used IMF data from ACE/WIND spacecrafts. We looked for correlations between the FD profile and that of the one-hour averaged IMF. We wanted to find out whether if the diffusion of high-energy protons into the large scale magnetic field is the cause of the lag observed between the FD and the IMF. Results. The enhancement of the IMF associated with FDs occurs mainly in the shock-sheath region, and the turbulence level in the magnetic field is also enhanced in this region. The observed FD profiles look remarkably similar to the IMF enhancement profiles. The FDs typically lag behind the IMF enhancement by a few hours. The lag corresponds to the time taken by high-energy protons to diffuse into the magnetic field enhancement via cross-field diffusion. Conclusions. Our findings show that high-rigidity FDs associated with CMEs are caused primarily by the cumulative diffusion of protons across the magnetic field enhancement in the turbulent sheath region between the shock and the CME.

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Section: Introductionmentioning

confidence: 83%

How are Forbush decreases related to interplanetary magnetic field enhancements?

Arunbabu

Antia

Dugad

et al. 2015

A&A

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“…The GRAPES-3 (Gamma Ray Astronomy at PeV EnergieS Phase-3) extensive air shower (EAS) array [60] has been designed to have one of the most compact configurations of the conventional type arrays with only 8 m separation between adjacent detectors that are arranged in a symmetric hexagonal geometry. The final target is to have 15 rings with 721 detectors, covering a distance up to 120 m from the center of the array, the observations were started in 2000 with 217 detectors located within the inner 8 rings.…”

Section: The Initial Arraymentioning

confidence: 99%

“…Most of these muons pass through the detector located above the muon telescope, thus providing the distribution of the integrated-charge for the passage of minimum ionizing particles. Typical single particle response for a detector in terms of the distribution of integrated-charge (ADC value) follows the Landau distribution [60]. The most probable ADC value obtained from the calibration distribution for each detector is used to convert the signal observed in a shower to 'equivalent' number of particles.…”

Section: S K Guptamentioning

confidence: 99%

“…The GRAPES-3 observations of the muon multiplicity distributions (MMDs) [60,61] for several shower size 'N e ' groups, have been used to obtain the energy spectra of various nuclear groups in the primary cosmic ray flux in the energy range ~ 100-1000 TeV. Therefore, a sizable overlap in the energy range ~ 100-300 TeV of the GRAPES-3 data with the direct measurements was achieved, that helped in the selection of a specific hadronic interaction generator as the preferred model, for the simulation of the EAS at energies ~ 100-1000 TeV.…”

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confidence: 99%

“…While the final target is to have 15 rings with 721 detectors, covering a distance of up to 120 m from the center of the array, the observations were started in early 2000 with 217 detectors located within the inner 8 rings which now have increased to 400 detectors. To extend the dynamic range of the primary energy it was decided to measure the density of the particles in the EAS with an enhanced range of up to 5000 m -2 [60].…”

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High Energy Astroparticle Physics at Ooty and the GRAPES-3 Experiment

Gupta¹

2014

Proceedings of the Indian National Science Academy

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The astroparticle studies at Ooty have their roots going way back into the fifties, when studies using cosmic rays were initiated with cloud chambers of progressively larger sizes as the primary detector and measuring device to obtain properties of hadrons at high energies. This study was subsequently strengthened with the installation of a total absorption calorimeter and a modest extensive air shower array to probe the composition of the primary cosmic rays to very high energies. The discovery of pulsars provided a thrust for the exploration of these compact objects as the sources of γ-rays at TeV energies with the aid of atmospheric Cerenkov detectors in the seventies. With the rapid technological advances occurring during the subsequent years in detectors, electronics and computers, physicists world-wide were able to set up very large and remarkably sensitive experiments that were hard to imagine a decade earlier. With the increasing sophistication and complexity the modern experiments require participation of very large teams of scientists. This development has made the formation of collaboration of large number of physicists both experimental and theoretical, engineers, technicians etc., from a number of institutions and universities, a prerequisite for setting up any major experimental facility. The GRAPES-3 experiment is a collaboration of 34 scientists from 13 institutions, including 8 from India and 5 from Japan. The GRAPES-3 experiment contains a dense extensive air shower array operating with ~ 400 scintillator detectors and a 560 m 2 tracking muon detector (Em > 1 GeV), at Ooty in India. 25 % of scintillator detectors are instrumented with two fast photomultiplier tubes (PMTs) for extending the dynamic range to ~ 5x10 3 particles m -2. The scintillators, signal processing electronics and data recording systems were fabricated in-house to cut costs and optimize performance. The muon multiplicity distribution of the EAS is used to probe the composition of primary cosmic rays below the 'knee', with an overlap with direct measurements. Search for multi-TeV γ-rays from point sources is done with the aid of the muon detector. A good angular resolution of 0.7 o at 30 TeV, is measured from shadow of the Moon on the isotropic flux of cosmic rays. Sensitive limit on the diffuse flux of 100 TeV γ-rays is placed by using muon detector to filter out the charged cosmic ray background. The tracking muon detector allows sensitive measurements on the coronal mass ejections and solar flares through Forbush decrease events. We have major expansion plans to enhance the sensitivity of the GRAPES-3 experiment in the areas listed above. PACS

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1.6 Cosmic-ray detectors

Müller

2010

Landolt-Börnstein - Group VI Astronomy and Astrophysics

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GRAPES-3—A high-density air shower array for studies on the structure in the cosmic-ray energy spectrum near the knee

Cited by 98 publications

References 20 publications

How are Forbush decreases related to interplanetary magnetic field enhancements?

How are Forbush decreases related to interplanetary magnetic field enhancements?

High Energy Astroparticle Physics at Ooty and the GRAPES-3 Experiment

1.6 Cosmic-ray detectors

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