181 research outputs found
Numerical Studies on Time Resolution of Micro-Pattern Gaseous Detectors
The Micro-Pattern Gaseous Detectors offer excellent spatial and temporal
resolution in harsh radiation environments of high-luminosity colliders. In
this work, an attempt has been made to establish an algorithm for estimating
the time resolution of different MPGDs. It has been estimated numerically on
the basis of two aspects, statistics and distribution of primary electrons and
their diffusion in gas medium, while ignoring their multiplication. The effect
of detector design parameters, field configuration and the composition of gas
mixture on the resolution have also been investigated. Finally, a modification
in the numerical approach considering the threshold limit of detecting the
signal has been done and tested for the RPC detector for its future
implementation in case of MPGDs
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
and mesh hole pitch of 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
Experimental and numerical simulation of a TPC like set up for the measurement of ion backflow
Ion backflow is one of the effects limiting the operation of a gaseous
detector at high flux, by giving rise to space charge which perturbs the
electric field. The natural ability of bulk Micromegas to suppress ion feedback
is very effective and can help the TPC drift volume to remain relatively free
of space charge build-up. An efficient and precise measurement of the backflow
fraction is necessary to cope up with the track distortion due to the space
charge effect. In a subtle but significant modification of the usual approach,
we have made use of two drift meshes in order to measure the ion backflow
fraction for bulk Micromegas detector. This helps to truly represent the
backflow fraction for a TPC. Moreover, attempt is taken to optimize the field
configuration between the drift meshes. In conjunction with the experimental
measurement, Garfield simulation framework has been used to simulate the
related physics processes numerically
On the localization properties of an RPWELL gas-avalanche detector
A study of the localization properties of a single-element Resistive Plate
WELL (RPWELL) detector is presented. The detector comprises of a single-sided
THick Gaseous Electron Multiplier (THGEM) coupled to a segmented readout anode
through a doped silicate-glass plate of 10 cm bulk
resistivity. Operated in ambient Ne/(5CH) gas, the detector has been
investigated with 150 GeV muons at CERN-SPS. Signals induced through the
resistive plate on anode readout strips were recorded with APV25/SRS
electronics. The experimental results are compared with that of Monte Carlo
simulations. The effects of various physics phenomena on the position
resolution are discussed. The measured position resolution in the present
configuration is 0.28 mm RMS - compatible with the holes-pattern of the
multiplier. Possible ways for improving the detector position resolution are
suggested
3D Simulation of Electron and Ion Transmission of GEM-based Detectors
Time Projection Chamber (TPC) has been chosen as the main tracking system in
several high-flux and high repetition rate experiments. These include on-going
experiments such as ALICE and future experiments such as PANDA at FAIR and ILC.
Different activities were carried out on the adoption
of Gas Electron Multiplier (GEM) as the gas amplification stage of the
ALICE-TPC upgrade version. The requirement of low ion feedback has been
established through these activities. Low ion feedback minimizes distortions
due to space charge and maintains the necessary values of detector gain and
energy resolution. In the present work, Garfield simulation framework has been
used to study the related physical processes occurring within single, triple
and quadruple GEM detectors. Ion backflow and electron transmission of
quadruple GEMs, made up of foils with different hole pitch under different
electromagnetic field configurations (the projected solutions for the ALICE
TPC) have been studied. Finally a new triple GEM detector configuration with
low ion backflow fraction and good electron transmission properties has been
proposed as a simpler GEM-based alternative suitable for TPCs for future
collider experiments
Investigation of heat-acid induced coagulation behaviour of whole milk systems employing front-face fluorescence spectroscopy
The heat-acid-induced coagulation behaviour of whole milk system (buffalo, cow and mixed milk) was studied by steady-state fluorescence spectroscopy exploiting tryptophan as a marker molecule. The varied molecular environment of tryptophan residues in the raw milk systems exerted different fluorescence properties. During the coagulation process, cow milk exhibited significant quenching and bathochromic shift in the emission spectra which was attributed to the low buffering ability and high hydration capacity of cow milk caseins. The results indicated that tryptophan residues of cow milk experienced more dynamic environment throughout the reaction as compared to buffalo milk
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