121560504
Multi-muon events deep underground and ultra-high-energy collisions
The configurations of multi-muon events have been investigated in detail by a three-dimensional Monte-Carlo simulation, including recent features of high-energy collisions observed in a p-p collider. The average properties and topology of individual multi-muon events at depths 1800, 4200 and 5000 mWe underground are studied. Some criteria are suggested to identify average primary mass composition. The important link between multi-muon events and high multiplicity fluctuations or more copious multi-particle production in the energy range 106-107 GeV has been pointed out.
123120201
Angular resolution of the KGF experiment to detect ultra high energy gamma-ray sources
The performance of the EAS array at Kolar Gold Fields (working since 1984 and upgraded by 1987) is described. The array has been designed to search for sources of ultra high energy (UHE) photons. The array, the data recording and estimation of shower parameters are briefly described. The angular resolution of the array is discussed in detail. The authors demonstrate, using their data, that the shower front is not a plane and derive an expression for the correction to be applied to the observed time delays in each EAS before fitting a plane front. They suggest using an acceptance cone, dependent on the number of timing detectors used to estimate the arrival direction of EAS, for point source searches.
118499232
Search for UHE counter-parts of Gamma Ray Bursts
Several Gamma Ray Bursts detected in the keV energy range by the Burst and Transient Source Experiment (BATSE) have been observed by the Energetic Gamma Ray Experiment Telescope (EGRET) in the MeV/GeV energy range. The energy spectra of γ-rays in some of the bursts continues from keV to GeV without a break or any evidence for a high energy cut-off. If the same slope continues up to the PeV range the expected γ-ray flux falls within the sensitivity of the Extensive Air Shower array operating at the Kolar Gold Fields, India. In view of the enormous astrophysical implications of the results, we have conducted a systematic search for PeV γ-rays from the locations of about 39 high fluence GRB’s detected during April 1991 and March 1993. The results of a search from 8 highest fluence GRB’s are presented here.
118319689
Preliminary Results on Size spectrum and age parameter of EAS from KGF Experiment
122295365
Extensive air shower experiment at Kolar Gold Fields
Abstract 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.
122399752
The ALICE instrument and the measured cosmic ray elemental abundances
Abstract A Large Isotopic Composition Experiment (ALICE) is a balloon-borne spectrometer which can determine the elemental and isotopic composition of galactic cosmic rays with energies near 1 GeV/nucleon. ALICE was flown from Prince Albert, Canada in August 1987, and remained at float altitude (120000 feet) for 14.7 hours. In this paper, we describe the experimental methods and analysis which will be used for subsequent isotopic analysis. We obtained very precise charge resolution over the entire designed range: 0.10 and 0.16 charge units at neon and iron, respectively. Results on the galactic cosmic ray abundances and absolute fluxes of the elements from neon through nickel are reported.
118403081
Implications of a matter-radius measurement for the structure of Carbon-22
Abstract We study Borromean 2 n -halo nuclei using effective field theory. We compute the universal scaling function that relates the mean-square matter radius of the 2 n halo to dimensionless ratios of two- and three-body energies. We use the experimental value of the rms matter radius of 22 C measured by Tanaka et al. (2010) [3] to put constraints on its 2 n separation energy and the 20 C– n virtual energy. We also explore the consequences of these constraints for the existence of excited Efimov states in this nucleus. We find that, for 22 C to have an rms matter radius within 1 – σ of the experimental value, the two-neutron separation energy of 22 C needs to be below 100 keV. Consequently, this three-body halo system can have an excited Efimov state only if the 20 C– n system has a resonance within 1 keV of the scattering threshold.