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Metre, Ramesh
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Metre, Ramesh
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Metre, R.
Metre R.K.
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40 results
Now showing 1 - 10 of 40
- PublicationA study of the Moon shadow by using GRAPES-3 muon telescope(2022-03-18)
;Zuberi, M.; ;Chakraborty, M. ;Chandra, A. ;Dugad, S. R. ;Goswami, U. D. ;Gupta, S. K. ;Hariharan, B. ;Hayashi, Y. ;Jagadeesan, P.; ; ;Kawakami, S. ;Kojima, H. ;Mahapatra, S. ;Mohanty, P. K.; ;Muraki, Y. ;Nayak, P. K. ;Nonaka, T. ;Oshima, A. ;Pant, B. P. ;Pattanaik, D. ;Pradhan, G. ;Rakshe, P. S. ;Rameez, M.; ;Reddy, L. V. ;Sahoo, R. ;Scaria, R. ;Shibata, S. ;Tanaka, K.Varsi, F.The GRAPES-3 experiment is designed to perform precision studies of gamma-ray sources in the TeV-PeV energy region. It consists of 400 plastic scintillator detectors spanning an effective area of 25000 m2 and a large area (560 m2) muon telescope which records ∼ 4 x 109 muons every day. With the recent installation of an improved triggerless data acquisition (DAQ) system, the information related to every muon is recorded with a timing resolution of 10 ns. The angular resolution and pointing accuracy of the upgraded muon telescope has been validated by characterizing the shadow of the moon among recorded muons. Here, the details of the analysis and results, as well as the simulation studies to account for the deflection of the particles in the Earth’s magnetic field will be presented. - PublicationVetoing the high energy showers in the GRAPES-3 experiment whose cores lie outside the array(2022-03-18)
;Chakraborty, M.; ;Chandra, A. ;Dugad, S. R. ;Goswami, U. D. ;Gupta, S. K. ;Hariharan, B. ;Hayashi, Y. ;Jagadeesan, P.; ; ;Kawakami, S. ;Kojima, H. ;Mahapatra, S. ;Mohanty, P. K.; ;Muraki, Y. ;Nayak, P. K. ;Nonaka, T. ;Oshima, A. ;Pant, B. P. ;Pattanaik, D. ;Pradhan, G. S. ;Rakshe, P. S. ;Rameez, M.; ;Reddy, L. V. ;Sahoo, R. ;Scaria, R. ;Shibata, S. ;Soni, J. ;Tanaka, K. ;Varsi, F.Zuberi, M.The GRAPES-3 experiment located in Ooty consists of an array of 400 plastic scintillator detectors spread over an area of 25000m2 and a large area (560 m2) muon telescope. Every day, the array records about 3 million showers induced by the interaction of primary cosmic rays in the atmosphere. One of the primary objectives of the experiment is to measure the energy spectrum and composition of the cosmic rays in the TeV-PeV energy range. However, some of the detected showers have cores outside the array. This fraction increases with energy due to the higher lateral spread of shower particles at higher energies. Identifying these events is thus crucial for accurate measurement of the cosmic ray energy spectrum. This work will describe simple cut based as well as machine learning based strategies for identifying and excluding such events and their impact on the cosmic ray energy spectrum as measured by the Bayesian unfolding technique. - PublicationA machine learning approach to identify the air shower cores for the GRAPES-3 experiment(2022-12-06)
;Chakraborty, M.; ;Chandra, A. ;Dugad, S. R. ;Goswami, U. D. ;Gupta, S. K. ;Hariharan, B. ;Hayashi, Y. ;Jagadeesan, P.; ; ;Kawakami, S. ;Kojima, H. ;Mahapatra, S. ;Mohanty, P. K.; ;Muraki, Y. ;Nayak, P. K. ;Nonaka, T. ;Oshima, A.; ;Pant, B. P. ;Pattanaik, D. ;Pradhan, G. S. ;Rameez, M.; ;Reddy, L. V. ;Sahoo, R. ;Scaria, R. ;Shibata, S. ;Tanaka, K. ;Varsi, F.Zuberi, M.The GRAPES-3 experiment located in Ooty consists of a dense array of 400 plastic scintillator detectors spread over an area of 25,000 m2 and a large area (560 m2) tracking muon telescope. Everyday, the array records about 3 million showers in the energy range of 1 TeV - 10 PeV induced by the interaction of primary cosmic rays in the atmosphere. These showers are reconstructed in order to find several shower parameters such as shower core, size, and age. High-energy showers landing far away from the array often trigger the array and are found to have their reconstructed cores within the array even though their true cores lie outside, due to reconstruction of partial information. These showers contaminate and lead to an inaccurate measurement of energy spectrum and composition. Such showers are removed by applying quality cuts on various shower parameters, manually as well as with machine learning approach. This work describes the improvements achieved in removal of such contaminated showers with the help of machine learning. - PublicationZenith angle dependence of pressure effect in GRAPES-3 muon telescope(2022-03-18)
;Zuberi, M.; ;Chakraborty, M. ;Chandra, A. ;Dugad, S. R. ;Goswami, U. D. ;Gupta, S. K. ;Hariharan, B. ;Hayashi, Y. ;Jagadeesan, P.; ; ;Kawakami, S. ;Kojima, H. ;Mahapatra, S. ;Mohanty, P. K.; ;Muraki, Y. ;Nayak, P. K. ;Nonaka, T. ;Oshima, A. ;Pant, B. P. ;Pattanaik, D. ;Pradhan, G. S. ;Rakshe, P. S. ;Rameez, M.; ;Reddy, L. V. ;Sahoo, R. ;Scaria, R. ;Shibata, S. ;Soni, J. ;Tanaka, K.Varsi, F.A large area (560 m2) muon telescope in the GRAPES-3 experiment at Ooty, India records muon intensity at high cutoff rigidities (Rc) varies from 14–32 GV along 169 independent directions spanning a field of view of 2.3 sr. The threshold energy of the recorded muons is sec(θ) GeV along a direction with a zenith angle (θ) and with the average angular accuracy of ∼4σ. The directional capabilities of the muon telescope are exploited for studying the effect of atmospheric pressure on the muon flux as a function of Rc. It is observed that the barometric coefficients relationship with logarithmic Rc can be well described by second-order polynomial function with a high Spearman Rank correlation coefficient of 0.99. - PublicationHydrothermal synthesis and characterization of nanostructured nickel vanadate for supercapacitor and photocatalytic applications(2023-12-01)
;Naik R, Lakshmana ;Narsaiah, T. Bala ;Justin, P. ;Khasim, Syed ;Kumar, A. Naveen ;Raghavendra, N.; Ravikumar, C. R.We successfully synthesised nickel vanadate (NiVO3) nanocomposite by an inexpensive hydrothermal technique. Several analytical methods have been employed to characterise the synthesised nanocomposite. The crystal structure of NiVO3 is orthorhombic, and its crystallite size is around 10.3 nm. The NiVO3 nanocomposite has an optical band gap of 2.62 eV from the absorption spectra analysis. At a current density of 5 Ag−1, the NiVO3 nanocomposite exhibits a specific capacitance value of 398 Fg−1 and a retention rate of almost 90% after 2000 cycles. Furthermore, stability studies show that at a current density of 5 Ag−1, 90% of the capacitance is retained for 4000 cycles. The photocatalytic studies to break down the industrial pollutant Fast Orange Red (F-OR) dye show a 98.7% decolourization rate after 120 min of exposure to UV light irradiation. These features promote the creation of such nanocomposites for practical energy and environmental applications while providing a deeper understanding of the material’s characteristics. - PublicationLuminescent Pyrene-Decorated Organotin Compounds: Observation of Monomer and Excimer Emission(2019-03-06)
;Pandey, Mrituanjay D.; ;Kundu, Subrata ;Mahanti, Bani; ;Gopal, KandasamyChandrasekhar, VadapalliThe pyrene-decorated luminescent organotin compounds Ph3SnO2CPyr (1), [(Bz2Sn)2(μ3-O)(μ-OH)(O2CPyr)]2·2EtOH (2), and t-Bu2Sn[O2CPyr]2 (3) were synthesized from a one-pot reaction between pyrene-1-carboxylic acid (PyrCO2H) and the appropriate organotin precursors. The molecular and crystal structures of 1-3 were determined by single-crystal X-ray diffraction analyses, which reveal rich supramolecular architectures in their crystal structures. The luminescence properties of these compounds were studied in solution as well as in the solid state. While in the solid state all of the compounds reveal excimer bands, in solution, strong monomer emission is seen. Fluorescence lifetime measurements revealed (365 nm) that the average lifetimes of 1-3 in solution could be estimated as 4.97 ns (1), 4.69 ns (2), and 6.93 ns (3). - PublicationMeasurement of large angle muon flux in GRAPES-3 experiment using triggerless DAQ system(2022-03-18)
;Hariharan, B. ;Hariharan, B.; ;Alt, T. ;Chakraborty, M. ;Chandra, A. ;Dugad, S. R. ;Goswami, U. D. ;Gupta, S. K. ;Hayashi, Y. ;Jagadeesan, P.; ; ;Kawakami, S. ;Kojima, H. ;Lindenstruth, V. ;Mahapatra, S. ;Manjunath, K. ;Mohanty, P. K.; ;Muraki, Y. ;Nayak, P. K. ;Nonaka, T. ;Oshima, A. ;Pant, B. P. ;Pattanaik, D. ;Pradhan, G. S. ;Rakshe, P. S. ;Rameez, M.; ;Reddy, L. V. ;Sahoo, R. ;Scaria, R. ;Shareef, M. S. ;Shibata, S. ;Soni, J. ;Sureshkumar, R. ;Tanaka, K. ;Varsi, F.Zuberi, M.The large area muon telescope of GRAPES-3 has been operating continuously for more than two decades with a DAQ which has several limitations. At present, this DAQ is in the process of being upgraded with a FPGA based system. The new DAQ system is designed to be triggerless and capable of recording every hit from the 3712 proportional counters along with a time-stamp (10 ns resolution) which has significantly expanded the physics horizon of the experiment. This triggerless feature allows the detection of muons beyond the nominal zenith range of the current system (θ<45◦). The upgraded DAQ system has been deployed for 25% of the telescope. An offline software trigger has been developed for the reconstruction of muon tracks by using the timing and pulse height information of each hit in the raw data. For the first time the muons are reconstructed in the entire zenith angle range. The extensive air showers (EAS) at large angles can be studied through the muon component. We present measurements of the flux of the large angle muons and their correlation with EAS triggers. - PublicationSearch for gamma rays above 30 TeV from the Crab Nebula with the GRAPES-3 experiment(2022-03-18)
;Pattanaik, D.; ;Chakraborty, M. ;Chandra, A. ;Dugad, S. R. ;Goswami, U. D. ;Gupta, S. K. ;Hariharan, B. ;Hayashi, Y. ;Jagadeesan, P.; ; ;Kawakami, S. ;Kojima, H. ;Mahapatra, S. ;Mohanty, P. K.; ;Muraki, Y. ;Nayak, P. K. ;Nonaka, T. ;Oshima, A. ;Pant, B. P. ;Pradhan, G. S. ;Rakshe, P. S. ;Rameez, M.; ;Reddy, L. V. ;Sahoo, R. ;Scaria, R. ;Shibata, S. ;Soni, J. ;Tanaka, K. ;Varsi, F.Zuberi, M.The GRAPES-3 is a high-altitude, near-equator extensive air shower array at Ooty, India which is designed to observe cosmic and gamma-rays in TeV-PeV energy range. It consists of a dense array of 400 scintillator detectors operating in conjunction with a 560 m2 area muon telescope. Due to recent improvements in the measurements of shower arrival time and corrections for shower front curvature based on shower size and age, the angular resolution of the array has been significantly improved. By leveraging the resultant improved angular resolution and an efficient rejection of the cosmic ray background using the muon content of the shower, a search for gamma-rays above 30 TeV from the Crab Nebula has been performed. The results will be presented during the conference. - PublicationAn Advanced Triggerless Data Acquisition System for the GRAPES-3 Muon Detector(2022-03-18)
; ; ;Alt, T. ;Chakraborty, M. ;Chandra, A. ;Dugad, S. R. ;Goswami, U. D. ;Gupta, S. K. ;Hariharan, B. ;Hayashi, Y. ;Jagadeesan, P.; ;Kawakami, S. ;Kojima, H. ;Lindenstruth, V. ;Mahapatra, S. ;Manjunath, K. ;Mohanty, P. K.; ;Muraki, Y. ;Nayak, P. K. ;Nonaka, T. ;Oshima, A. ;Pant, B. P. ;Pattanaik, D. ;Pradhan, G. S. ;Rakshe, P. S. ;Rameez, M.; ;Reddy, L. V. ;Sahoo, R. ;Scaria, R. ;Shareef, M. S. ;Shibata, S. ;Soni, J. ;Sureshkumar, R. ;Tanaka, K. ;Varsi, F.Zuberi, M.The large area (560 m2) muon telescope at Gamma Ray Astronomy at PeV Energies phase -3 (GRAPES-3) experiment in Ooty, India was designed primarily to study extensive air showers (EAS) and made operational in the year 1998. It has turned out to be a unique instrument capable of studying exotic phenomena by introduction of a new parallel data acquisition system (DAQ) in year 2000 to measure the muon directional flux. The recent discoveries of transient weakening of Earth’s magnetic shield probed by a Cosmic Ray Burst [1] and measurement of the electrical properties of a thundercloud through muon imaging [2] has demonstrated the capabilities of this instrument. The design and deployment of a new triggerless muon data acquisition system (TM-DAQ) using Field Programmable Gate Array (FPGA) would enhance the present capabilities and open a new window on several physics fronts such as, a) precise measurement of the muon flux for thunderstorm studies, b) study of large angle EAS using the muon component, c) search for exotic particles characterized by early or delayed arrivals. We present here the salient features of the TM-DAQ along with initial observations - PublicationMeasurement of the improved angular resolution of GRAPES-3 EAS array by the observation of the Moon shadow(2022-03-18)
;Pattanaik, D.; ;Chakraborty, M. ;Chandra, A. ;Dugad, S. R. ;Goswami, U. D. ;Gupta, S. K. ;Hariharan, B. ;Hayashi, Y. ;Jagadeesan, P.; ; ;Kawakami, S. ;Kojima, H. ;Mahapatra, S. ;Mohanty, P. K.; ;Muraki, Y. ;Nayak, P. K. ;Nonaka, T. ;Oshima, A. ;Pant, B. P. ;Pradhan, G. S. ;Rakshe, P. S. ;Rameez, M.; ;Reddy, L. V. ;Sahoo, R. ;Scaria, R. ;Shibata, S. ;Soni, J. ;Tanaka, K. ;Varsi, F.Zuberi, M.The Moon acts as a shield against the cosmic rays, preventing them from reaching the earth, which gives rise to a deficit in the flux along the direction of the Moon. The observed deficit can be used for obtaining the absolute calibration of the angular resolution and to verify the pointing accuracy of the array. GRAPES-3 is an extensive air shower experiment located at Ooty, India consisting of a dense array of scintillator detectors. It records ∼109 showers per year with a median energy of 10 TeV. With the precise determination of the arrival time of shower particles and an accurate correction for the shower front curvature, a major improvement in the angular resolution of the array has been achieved. This was done by the array division methods including the left-right and even-odd methods. Here, we present a verification of the angular resolution estimates and the pointing accuracy by observing the shadow of the Moon in the cosmic ray flux.