The Sunyaev-Zel’dovich Effect as a Probe of the Large Scale Structure of the Universe

The Sunyaev-Zel’dovich effect (S-Z effect) is a distortion in the cosmic microwave back- ground radiation (CMBR) [1, 2, 3, 4] due to the inverse Compton scattering of CMBR photons by the electrons in the intra-cluster medium (ICM) [5, 6, 7, 8, 9]. The effect is an interaction between Cosmic Microwave Background Radiation photons and the free electrons in the dense cores of galaxy clusters. These cores of clusters of galaxies are thought to contain hot ionized gas at 107K [10]. This hot ionized gas is visible as X-ray emission. The free electrons in the gas contain a significant amount of kinetic energy, making them good sources for S-Z effect

Constraining the Cosmological Parameters and the Underlying Theoretical Models with CMB Anisotropy and Polarization Measurements

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Studies on the Composition, Distribution and Detection of Dark Matter in the Universe

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Design, Development and Characterization of Glass Resistive Plate Chambers for Muon Detection”

Resistive plate chambers (RPC) are rugged and affordable gas detectors that have found extensive use in high energy physics and astroparticle experiments [1]. The main features of these counters are the very large pulse height, reduced cost per unit area and good (about 1ns) time resolution. The field has enjoyed very lively progress in recent years, including the introduction of new (avalanche) mode of operation, improvement of the time resolution for minimum ionizing particles, and the achievement of position resolution of a few tens of micrometers [2]. These new developments have extended the range of high energy physics experiment applications and promise new developments in medical imaging. The first detector mounting resistive electrodes was the Planar Spark Chamber (PSC), which was built by Pestov. The signal was extracted by means of copper strips glued on the anode. The Pestov Spark Counter [3, 4] with a 0.1 mm gap achieved a time resolution of 25 ps. The very thin gap combined with the high values of the electric field (500 kV/cm) demand a very good surface smoothness of the electrodes. The detector while operated at a large overpressure, viz. at 12 bars, ensures a sufficiently large number of primary electron-ion pairs in the thin gap which in turn results in good detection efficiency. Figure 1.1 shows a simple schematic of a Pestov Spark Counter. Resistive plate chambers were introduced by R. Santonico and R. Cardarelli [5] as a practical alternative to the remarkable ‘localized discharge spark counter’, which ultimately reached a time resolution of 25 ps. The resulting detector free from damaging discharges and enjoying a good time resolution has found a good acceptance in high energy and astro-particle physics experiments. RPC is based on essentially the same principle as that of Pestov’s Planar Spark Chamber [6]. Nevertheless drastic simplifications were introduced in its realization