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Radioactivity is a form of natural radiation, and it is measured in becquerels (Bq) using the SI system. Both human activities and natural processes can produce radioactivity. For this study, three regions on the South Tamilnadu coastline in India, namely Manavalakurichi, Colachel, and Kudankulam, were chosen. A dual-channel alpha-beta counter was used to measure gross alpha and beta activity based on the scintillation principle. The radioactive nuclide activity concentrations in soil and water were measured, and the levels were considered acceptable. The alpha and beta radiation levels in soil and water samples did not significantly differ. The study's results suggest that the risk of radiation danger in the study area is not significantly increased because the values obtained are within the generally accepted limits. The ANOVA experiments also revealed that there was no significant difference in the gross alpha and beta activity of soil and water samples. Moreover, the alpha and beta activity in drinking water was lower in all three areas than what is recommended by the WHO. Therefore, it can be concluded that the drinking water in these three regions is safe for consumption. [ABSTRACT FROM AUTHOR]

The Facility for Antiproton and Ion Research (FAIR) is a future project at GSI which will extend hadron physics studies up to the charm meson region using antiproton beams together with a state-of-the-art detector antiproton annihilation at Darmstadt (PANDA). The physics aim, in a broader sense, is to address the fundamental problems of hadron physics and aspects of quantum chromo-dynamics (QCD) at low energies. The proposed work in India will consist of several parts: R&D studies of silicon micro-strip detector, development of a scintillator hodoscope with silicon photomultiplier (SiPM) readout, studies of SiPM as photon counter and simulation studies of the detector design as well as physics case studies. The present article describes the physics motivation and initial progress made towards achieving these goals. [ABSTRACT FROM AUTHOR]

A recently published article in Science [A. Cho, Science, 318(5852), 896 (2007)] by the Pierre Auger Laboratory has helped pinpoint the source of ultrahigh energy cosmic rays, which are the most energetic particles known in the universe. The sources found indicate support for the “active galactic nuclei” theory, which is that the ultrahigh energy cosmic rays come from supermassive black holes found at the centers of galaxies. The Pierre Auger Observatory (website: AUGER EXPERIMENT, www.auger.org) records the extensive air showers through an array of 1600 particle detectors placed 1.5 km apart in a grid spread across 3000 km2. The window of TeV gamma-ray astrophysics was opened less than 2 decades ago, when the Crab Nebula was detected for the first time. After several years of development, the technique used by imaging atmospheric Cherenkov telescopes such as HESS and MAGIC is now allowing to conduct sensitive observations in the TeV regime. Water Cherenkov instruments such as Milagro are also providing results. Different types of extragalactic and galactic sources have been detected, showing a variety of interesting phenomena that are boosting theory in very high energy gamma-ray astrophysics. Here I review basic cosmic rays, the detection methods, and then present a simulation study of the gamma-ray astronomy at PeV energies—phase 3 (GRAPES3) experiment. GRAPES-3 is a scintillator detector array equipped with a muon detector tracker at Ooty, India. The capabilities of the array can be enhanced by changing the detector separation, etc. This can reduce the energy threshold (Eth), improve the angular resolution of the array, and hence improve the significance that the array can get from a gamma-ray source. This makes the array suitable to be used for gamma-ray source detection and studies. In the present article a study of the effect of reduction in detector separation, on the performance of the array, using simulation techniques has been presented. Simulation shows that reducing the detector separation by a factor of 2 results in a factor of 2 reduction in Eth. It also gives direction of study for further improvement in the angular resolution and significance, specifically from a Crab Nebula-like spectrum. [ABSTRACT FROM AUTHOR]