arXiv subjects

Nayana Majumdar

Publications and source records attributed to Nayana Majumdar.

At least 37 records · Page 2Linked to original sources

arXiv2022

Numerical calculation of RPC time resolution

Resistive Plate Chamber (RPC) is a gaseous detector, known for its good spatial resolution and excellent time resolution. Due to its fast response and excellent time resolution, it is used for both triggering and timing purpose. But the time resolution of RPC is dependent on the detector geometry, applied voltage and the gas mixture used for detector operation. In this work, we have tried to develop a numerical model to estimate the time resolution of the detector. The model is developed using COMSOL Multiphysics, a commercially available finite element method solver. Using the primary ionization information from HEED and the electron transport properties from MAGBOLTZ, the model solves the Boltzmann equations to simulate the avalanche in the detector and finds the time to cross a previously determined threshold current, which is used to measure the time resolution of the detector.

physics.ins-det↗

arXiv2021

Numerical estimation of discharge probability in GEM-based detectors

Discharge probability in GEM-based gaseous detectors has been numerically estimated using an axisymmetric hydrodynamic model. Initial primary charge configurations in the drift region, obtained using Heed and Geant4, are found to have significant effect on the subsequent evolution of detector response. Simulation of energy resolution has been performed to establish the capability of the hydrodynamic model to capture statistical nature of the experimental situation. Finally, single and triple GEM configurations exposed to alpha sources have been simulated to estimate discharge probability which have been compared with available experimental data. Despite the simplifying and drastic assumptions in the numerical model, the comparisons are encouraging.

physics.ins-det↗

arXiv2021

Numerical Qualification of Eco-Friendly Gas Mixtures for Avalanche-Mode Operation of Resistive Plate Chambers in INO-ICAL

Numerical qualification of an eco-friendly alternative gas mixture for avalanche mode operation of Resistive Plate Chambers is the soul of this work. To identify the gas mixture, a numerical model developed elsewhere by the authors has been first established by comparing the simulated figure of merits (efficiency and streamer probability) with the experimental data for the gas mixture used in INO-ICAL. Then it has been used to simulate the same properties of a gas mixture based on argon, carbon di-oxide and nitrogen, identified as potential replacement by studying its different properties. Efficacy of this eco-friendly gas mixture has been studied by comparing the simulated result with the standard gas mixture used in INO-ICAL as well as with experimental data of other eco-friendly hydrofluorocarbon (HFO1234ze) based potential replacements. To increase the efficacy of the proposed gas mixture, studies of the traditional way (addition of a little amount of SF$_6$) and an alternative approach (exploring the option of high-end electronics) were carried out.

physics.ins-det↗

arXiv2021

Numerical Evaluation of a muon tomography system for imaging defects in concrete structures

Among numerous applications of muon tomography, deployment in civil structures has caught attraction of many recently. In this work, the appropriateness of muon scattering tomography to detect defects in concrete structures has been studied numerically. A few basic concrete structures that are frequently used in civil construction, have been considered as test cases. A simulation has been performed on Geant4 platform where an imaging setup built with several gaseous ionization detectors, having a specific spatial resolution for tracking the muons, have been modeled. The images of the test cases with and without the defect have been simulated for a month-long exposure of cosmic muons on the basis of their scattering from the composite concrete structures. The images have been compared using t-test to evaluate the performance of the imaging setup in identifying the defects. Further processing of the images has been done with a pattern recognition method proposed in our earlier work to improve defect identification. The efficacy of the said method has been evaluated in terms of the PRM-score devised in this work. The limitation and advantages of the present application of the muon scattering tomography encompassing the imaging and image processing technique in non-destructive evaluation of concrete structures have been discussed.

hep-ex↗

arXiv2020

Fast simulation of avalanche and streamer in GEM detector using hydrodynamic approach

A fast, hydrodynamic numerical model has been developed on the COMSOL Multi-physics platform to simulate the evolution and dynamics of charged particles in gaseous ionization detectors based on the Gaseous Electron Multipliers (GEM). Effects of using two-dimensional (2D), 2D axisymmetric and three-dimensional(3D) models of the detectors have been analyzed to choose the optimum configuration. The chosen model has been used to follow the entire operating regime of single, double and triple GEM detectors, including avalanche and streamer mode operations. The accumulation of space charge, its contribution towards the distortion of the applied electric field and production of streamers have been investigated in fair detail using the optimized model.

physics.ins-det↗

arXiv2020

Studies on charging-up of single Gas Electron Multiplier

Mechanisms of charging-up and charging-down of Gas Electron Multiplier (GEM) have been studied. Experimental investigations have been carried out on both dielectric polarization and radiation charging of GEMs. Environmental parameters, such as pressure and temperature have been monitored to normalize their effects on the charging-up and charging-down measurements. Variation in gain due to the combined, as well as individual, effects of the mentioned parameters has been illustrated.

physics.ins-det↗

arXiv2020

Study of Streamer Development in Resistive Plate Chamber

This work has been carried out to simulate a Resistive Plate Chamber and corroborate it with experimental measurements in order to develop a numerical tool for studying the performance of the device for any gas mixture. This will allow us to explore the feasibility of operating these chambers in their avalanche mode within the Iron Calorimeter setup at India-based Neutrino Observatory with any eco-friendly substitute. The simulation has considered a hydrodynamic model of charge transport to emulate the electronic and ionic growths in the device as a function of the applied voltage which determines its working mode as either of the avalanche or streamer. In order to validate, the simulation result has been compared with compatible experimental data available in the literature.

physics.ins-det↗

arXiv2020

Precise Tracking of Cosmic Muons using Time over Threshold property of NINO ASICs

This work reports a cost-effective, simple front-end readout and DAQ of a RPC-based muon scattering tomography system under construction. The Time-over-threshold property of NINO ASICs has been exploited to achieve precise tracking by extraction of position information. The use of a low-cost FPGA for event selection and TOT measurement has been demonstrated for a prototype RPC which has been triggered by a cosmic ray hodoscope of three plastic scintillators. The relation between input pulse width and TOT has been established by analyzing the waveforms of the RPC signals. The TOT profile at different working voltages has been obtained by the FPGA and it has been fitted with the Gaussian distribution. Its standard deviation represents an estimate of the tracking precision.

physics.ins-det↗

arXiv2020

Numerical study of track distortion in the Large Prototype TPC with end-plate based on bulk Micromegas

The present $\mathrm{R}\&\mathrm{D}$ activities for the International Large Detector Time Projection Chamber (ILD-TPC) concern the adoption of the micro pattern devices for the gaseous amplification stage. Seven Micromegas modules which are commissioned on the end-plate of a Large Prototype TPC (LPTPC) at DESY, were tested with a 5 GeV electron beam, under a 1 T magnetic field. During experiments, reduced signal sensitivity as well as distortion in the reconstructed track was observed at the boundaries of these modules. Electrostatic field inhomogeneity near the module boundaries was considered to be the possible major reason behind these observations. In the present work, this hypothesis has been explored using the Garfield simulation framework. It has been possible to contain the computational complexity of the problem with suitable simplifications. Qualitative and quantitative agreements with experimental results have been achieved. Possibility of mitigating the problems has been proposed using the same simulation framework.

physics.ins-det↗

arXiv2020

Charge sharing in single and double GEMs

The Gas Electron Multiplier (GEM) has become a widely used technology for high-rate particle physics experiments like COMPASS, LHCb and are being used as the readout system for the upcoming upgrade version of other experiments such as ALICE TPC. Radiation hardness, ageing resistance and stability against discharges are main criteria for long-term operation of such detectors in high-rate experiments. In particular, discharge is a serious issue as it may cause irreversible damages to the detector as well as the readout electronics. The charge density inside the amplification region is the limiting factor for detector stability against discharges. By using multiple devices and thus, sharing the electron multiplication in different stages, maximum sustainable gain can be increased by several orders of magnitude. A common explanation for this is connected to the transverse electron diffusion, widening of the electron cloud and reducing the charge density in the last multiplier. However, this has not been verified yet. In our work, we are using Garfield simulation framework as a tool to extract the information related to the transverse size of the propagating electron cloud and thus, to estimate the charge density in the GEM holes for multiple stages. For a given gas mixture, we will present the initial results of charge sharing using single and double GEM detectors under different electric field configurations and its effect on other measurable detector parameters such as single point position resolution.

physics.ins-det↗

arXiv2020

Material Discrimination in Cosmic Muon Imaging using Pattern Recognition Method

This work reports numerical simulations and statistical tests carried out to study the performance of a prototype imaging setup to be developed for material discrimination using Muon Scattering Tomography (MST). The reconstructed images have been processed with a Pattern Recognition Method (PRM) to discriminate the low-Z and high-Z materials. The same method has been applied to examine the performance of the setup in recognizing the shape of the test objects. Design parameters of the setup, such as area of the muon detectors, their physical placement, along with their spatial resolution, etc. have been discussed. To evaluate the efficacy of the newly proposed PRM, the results have been compared to another technique based on cluster finding.

physics.ins-det↗

arXiv2019

Numerical studies on effect of operating conditions and geometrical components on the timing response and efficiency of RPC

A detailed numerical simulation has been performed to investigate the timing properties of a standard RPC geometry in order to optimize its application in INO-ICAL experiment designed for studying atmospheric neutrinos. The timing information provided by the RPC is an important observable in the experiment to determine the direction of the neutrinos. Effects of various operating conditions and design components on the RPC timing response, mainly the average signal arrival time and the time resolution have been studied in this context. The dependence of the detector efficiency on the same parameters has also been presented.

physics.ins-det↗

arXiv2018

Material Identification with Cosmic Ray Muons using RPCs

We plan to build an imaging setup for material identification utilizing the Coulomb scattering of cosmic ray muons due to their interaction with the materials and tracking their trajectories with RPCs. To begin with, we consider a setup of six RPCs stacked in a parallel manner to read the position and timing information of the muons before and after their interaction with a phantom of a given material using a set of three RPCs for each phase. Here we present a simulation work carried out to study the image formation of the phantom of several materials using the present setup. A detailed modeling of the imaging system consisting of six RPCs was done using GEANT4. Cosmic Ray Library (CRY) was used for generation of particles with the appropriate distribution of energies and momenta. Three reconstruction algorithms were followed for material identification and image reconstruction, viz. Point of Closest Approach (POCA), Iterative POCA and the Binned Clustering Algorithm. A weighted metric discriminator was calculated for target object identification. Using the algorithms, the imaging of the area of interest lying between the two layers of RPCs was done. The time required to discriminate target objects and do the image reconstruction has been studied.

physics.ins-det↗

arXiv2017

Measurement and simulation of two-phase CO$_2$ cooling for the AFTER electronics of the Micromegas modules for a Large Prototype of a Time Projection Chamber

The readout electronics of a Micromegas (MM) module consume nearly 26 W of electric power, which causes the temperature of electronic board to increase upto $70\,^{\circ}{\rm C}$. Increase in temperature results in damage of electronics. Development of temperature gradient in the Time Projection Chamber (TPC) may affect precise measurement as well. Two-phase CO$_2$ cooling has been applied to remove heat from the MM modules during two test beam experiments at DESY, Hamburg. Following the experimental procedure, a comprehensive study of the cooling technique has been accomplished for a single MM module by means of numerical simulation. This paper is focused to discuss the application of two-phase CO$_2$ cooling to keep the temperature below $30\,^{\circ}{\rm C}$ and stabilized within $0.2\,^{\circ}{\rm C}$.

physics.ins-det↗

arXiv2017

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.

physics.ins-det↗

arXiv2017

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 $\mathrm{R}\&\mathrm{D}$ 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.

physics.ins-det↗

arXiv2017

Physics Potential of the ICAL detector at the India-based Neutrino Observatory (INO)

The upcoming 50 kt magnetized iron calorimeter (ICAL) detector at the India-based Neutrino Observatory (INO) is designed to study the atmospheric neutrinos and antineutrinos separately over a wide range of energies and path lengths. The primary focus of this experiment is to explore the Earth matter effects by observing the energy and zenith angle dependence of the atmospheric neutrinos in the multi-GeV range. This study will be crucial to address some of the outstanding issues in neutrino oscillation physics, including the fundamental issue of neutrino mass hierarchy. In this document, we present the physics potential of the detector as obtained from realistic detector simulations. We describe the simulation framework, the neutrino interactions in the detector, and the expected response of the detector to particles traversing it. The ICAL detector can determine the energy and direction of the muons to a high precision, and in addition, its sensitivity to multi-GeV hadrons increases its physics reach substantially. Its charge identification capability, and hence its ability to distinguish neutrinos from antineutrinos, makes it an efficient detector for determining the neutrino mass hierarchy. In this report, we outline the analyses carried out for the determination of neutrino mass hierarchy and precision measurements of atmospheric neutrino mixing parameters at ICAL, and give the expected physics reach of the detector with 10 years of runtime. We also explore the potential of ICAL for probing new physics scenarios like CPT violation and the presence of magnetic monopoles.

physics.ins-det↗

arXiv2016

Numerical study on the effect of design parameters and spacers on RPC signal and timing properties

Numerical calculations have been performed to understand the reason for the observed non-uniform response of a Resistive Plate Chamber (RPC) in a few critical regions such as near edge spacers and corners of the device. In this context, the signal from a RPC due to the passage of muons through different regions has been computed. Also, a simulation of RPC timing properties is presented along with the effect of the applied field, gas mixture and geometrical components.

physics.ins-det↗