A large area muon tracking detector for ultra-high energy cosmic ray astrophysics—the GRAPES-3 experiment

Hayashi, Y.; Aikawa, Yuri; Gopalakrishnan, N. V.; Gupta, S. K.; Ikeda, N.; Ito, N.; Jain, Atul K.; John, A.; Karthikeyan, S.; Kawakami, S.; Kojima, Hiroshi; 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.2005.02.020

Cited by 102 publications

(72 citation statements)

References 36 publications

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“…The energy threshold of the telescope is sec (θ) GeV for the muons arriving along a direction with zenith angle θ. The observed muon rate of ∼3000 s −1 per module yields a total muon rate of ∼3 × 10 6 min −1 for the entire telescope (Hayashi et al 2005;Nonaka et al 2006). This high rate permits even a small change of 0.1% in the muon flux to be accurately measured over a time scale of ∼5 min, after appropriate corrections are applied for the time dependent variation in the atmospheric pressure (Mohanty et al 2013).…”

Section: Introductionmentioning

confidence: 99%

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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: 99%

“…The cutoff rigidity due to the geomagnetic field at Ooty is 17 GV along the vertical direction and varies from 14 to 42 GV across the 2.2 sr. field of view of the muon telescope. Details of the muon telescope are given in Hayashi et al (2005), Nonaka et al (2006), and Subramanian et al (2009).…”

Section: Introductionmentioning

confidence: 99%

How are Forbush decreases related to interplanetary magnetic field enhancements?

Arunbabu

Antia

Dugad

et al. 2015

A&A

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“…This feature of the GRAPES-3 experiment has turned out to be of critical importance in studying various transient phenomena including those of cosmic, solar or atmospheric origin. The pressure effect is also clearly seen in the muon counting rate [61].…”

Section: Rate Monitoringmentioning

confidence: 78%

“…However, the GRAPES-3 experiment [61] with its single large area (560 m 2 ) muon detector is attempting to reach a significantly higher level of sensitivity to the γ-initiated showers based on their small muon content, particularly at the sub-PeV energies, lower than those achieved by the CASA-MIA experiment.…”

Section: High Energy Astroparticle Physics At Ooty and The Grapes-3 Ementioning

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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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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