Performance Studies of Bulk Micromegas of Different Design Parameters

The present work involves the comparison of various bulk Micromegas detectors having different design parameters. Six detectors with amplification gaps of $64,~128,~192,~220 ~\mu\mathrm{m}$ and mesh hole pitch of $63,~78 ~\mu\mathrm{m}$ were tested at room temperature and normal gas pressure. Two setups were built to evaluate the effect of the variation of the amplification gap and mesh hole pitch on different detector characteristics. The gain, energy resolution and electron transmission of these Micromegas detectors were measured in Argon-Isobutane (90:10) gas mixture while the measurements of the ion backflow were carried out in P10 gas. These measured characteristics have been compared in detail to the numerical simulations using the Garfield framework that combines packages such as neBEM, Magboltz and Heed.Comment: arXiv admin note: text overlap with arXiv:1605.0289

Comparative study on charging-up of single, double and triple Gas Electron Multipliers (GEM)

In this paper, a detailed investigation has been carried out to understand the physics behind GEM charging-up and its effects on gain. Experiments have been performed on both double and triple GEM with the help of 55Fe X-ray source and a comparative study of these configurations along with the single GEM results observed in our previous work has been reported. The increase in gain due to polarization of GEM foil dielectric and reduction in gain due to charge accumulation on dielectric are studied for various field configurations and different radiation intensities

Ameliorating effect of quercetin against UV radiation-induced damage in Drosophila melanogaster

Quercetin is a plant flavonoid found in various fruits, leaves such as tea, vegetables and has been extensively studied due to its antioxidative, anticancer, anti-inflammatory and anti-neurodegenarative effects. UV radiation is harmful for human being as it may cause several complications such as skin cancer. Fruit fly (Drosophila sp.) has long been used as an arthropod model for genetics related studies. In the present study, the protective effect of quercetin is evaluated against UV-C radiation induced damage using Drosophila melanogaster. Pre-treatment with quercetin (10 µM) recovered the shortened lifespan caused by UV radiation and has also increased eclosion rate and the dose of quercetin is lower than the previously reported doses of other flavonoids. Flies subjected to moderate dose of UV radiation showed distinct abnormal characters such as incomplete abdominal pigmentation, curly wings or outstretched wings, whereas quercetin pretreatment showed no such abnormal characters or mutant phenotypes.  There is a considerable amount of change in the eclosed adult fly size, pupal size and pupal migration distance as well. Gel electrophoresis study of salivary gland DNA of D. melanogaster demonstrates the efficacy of quercetin in conferring protection to DNA against UV radiation-induced damage. Therefore, it can be concluded that quercetin may act as an effective protective agent against UV radiation-induced damage. DOI: http://dx.doi.org/10.5281/zenodo.358854

String Network and U-Duality

We discuss the generalization of recently discovered BPS configurations, corresponding to the planar string networks, to non-planar ones by considering the U-duality symmetry of type II string theory in various dimensions. As an explicit example, we analyze the string solutions in 8-dimensional space-time, carrying SL(3) charges, and show that by aligning the strings along various directions appropriately, one can obtain a string network which preserves 1/8 supersymmetry.Comment: 8 pages, latex, references added, minor modification