arXiv subjects

Deepak Tiwari

Publications and source records attributed to Deepak Tiwari.

6 recordsLinked to original sources

arXiv2025

Optical surface reflectivity characterization in water Cherenkov detectors: methodologies and industrial applications

Understanding the optical properties of various components in water Cherenkov (WC) neutrino experiments is essential for accurate detector characterization, which is critical for precise measurements. Of particular importance is the characterization of surface reflectivity within the Cherenkov volume. We present a methodology for surface reflectivity characterization using a goniometer setup, addressing the challenges associated with measurements in the air and water (or other optical media). Additionally, we discuss the broader implications of Bidirectional Reflectance Distribution Function (BRDF) measurements using a goniometer, including their industrial applications.

physics.ins-det↗

arXiv2024

Power Flow Analysis Using Deep Neural Networks in Three-Phase Unbalanced Smart Distribution Grids

Most power systems' approaches are currently tending towards stochastic and probabilistic methods due to the high variability of renewable sources and the stochastic nature of loads. Conventional power flow (PF) approaches such as forward-backward sweep (FBS) and Newton-Raphson require a high number of iterations to solve non-linear PF equations making them computationally very intensive. PF is the most important study performed by utility, required in all stages of the power system, especially in operations and planning. This paper discusses the applications of deep learning (DL) to predict PF solutions for three-phase unbalanced power distribution grids. Three deep neural networks (DNNs); Radial Basis Function Network (RBFnet), Multi-Layer Perceptron (MLP), and Convolutional Neural Network (CNN), are proposed in this paper to predict PF solutions. The PF problem is formulated as a multi-output regression model where two or more output values are predicted based on the inputs. The training and testing data are generated through the OpenDSS-MATLAB COM interface. These methods are completely data-driven where the training relies on reducing the mismatch at each node without the need for the knowledge of the system. The novelty of the proposed methodology is that the models can accurately predict the PF solutions for the unbalanced distribution grids with mutual coupling and are robust to different R/X ratios, topology changes as well as generation and load variability introduced by the integration of distributed energy resources (DERs) and electric vehicles (EVs). To test the efficacy of the DNN models, they are applied to IEEE 4-node and 123-node test cases, and the American Electric Power (AEP) feeder model. The PF results for RBFnet, MLP, and CNN models are discussed in this paper demonstrating that all three DNN models provide highly accurate results in predicting PF solutions.

eess.SY↗

arXiv2018

Prospects of indirect searches for dark matter annihilations in the earth with ICAL@INO

We study the prospects of detecting muon events at the upcoming Iron CALorimeter (ICAL) detector to be built at the proposed India-based Neutrino Observatory (INO) facility due to neutrinos arising out of annihilation of Weakly Interactive Massive Particles (WIMP) in the centre of the earth. The atmospheric neutrinos coming from the direction of earth core presents an irreducible background. We consider 50kt $\times$ 10 years of ICAL running and WIMP masses between 10-100 GeV and present 90 \% C.L. exclusion sensitivity limits on $σ_{SI}$ which is the WIMP-nucleon Spin Independent (SI) interaction cross-section. The expected sensitivity limits calculated for ICAL for the WIMP annihilation in the earth are more stringent than the limits obtained by any other indirect detection experiment. For a WIMP mass of ~$52.14 \textup{ GeV}$, where the signal fluxes are enhanced due to resonance capture of WIMP in earth due to Fe nuclei, the sensitivity limits, assuming 100\% branching ratio for each channel, are : $σ_{SI} =1.02\times 10^{-44}~cm^2$ for the $τ^{+} τ^{-}$ channel and $σ_{SI} =5.36\times 10^{-44} ~cm^2$ for the $b ~\bar{b}$ channel.

hep-ph↗

arXiv2018

Prospects of Indirect Searches for Dark Matter at INO

The annihilation of Weakly Interactive Massive Particles (WIMP) in the centre of the sun could give rise to neutrino fluxes. We study the prospects of searching for these neutrinos at the upcoming Iron CALorimeter (ICAL) detector to be housed at the India-based Neutrino Observatory (INO). We perform ICAL simulations to obtain the detector efficiencies and resolutions in order to simulate muon events in ICAL due to neutrinos coming from annihilation of WIMP in the mass range $m_χ= (3-100)$ GeV. The atmospheric neutrinos pose a major background for these indirect detection studies and can be reduced using the fact that the signal comes only from the direction of the sun. For a given WIMP mass, we find the opening angle $θ_{90}$ such that 90 \% of the signal events are contained within this angle and use this cone-cut criteria to reduce the atmospheric neutrino background. The reduced background is then weighted by the solar exposure function at INO to obtain the final background spectrum for a given WIMP mass. We perform a $χ^2$ analysis and present expected exclusion regions in the $σ_{SD}-m_χ$ and $σ_{SI}-m_χ$, where $σ_{SD}$ and $σ_{SI}$ are the WIMP-nucleon Spin-Dependent (SD) and Spin-Independent (SI) scattering cross-section, respectively. For a 10 years exposure and $m_χ=25$ GeV, the expected 90 \% C.L. exclusion limit is found to be $σ_{SD} < 6.87\times 10^{-41}$ cm$^2$ and $σ_{SI} < 7.75\times 10^{-43}$ cm$^2$ for the $τ^{+} τ^{-}$ annihilation channel and $σ_{SD} < 1.14\times 10^{-39}$ cm$^2$ and $σ_{SI} < 1.30\times 10^{-41}$ cm$^2$ for the $b~\bar b $ channel, assuming 100 \% branching ratio for each of the WIMP annihilation channel.

hep-ex↗

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↗

arXiv2015

Neutrino Physics with Non-Standard Interactions at INO

Non-standard neutrino interactions (NSI) involved in neutrino propagation inside Earth matter could potentially alter atmospheric neutrino fluxes. In this work, we look at the impact of these NSI on the signal at the ICAL detector to be built at the India-based Neutrino Observatory (INO). We show how the sensitivity to the neutrino mass hierarchy of ICAL changes in the presence of NSI. The mass hierarchy sensitivity is shown to be rather sensitive to the NSI parameters $ε_{eμ}$ and $ε_{eτ}$, while the dependence on $ε_{μτ}$ and $ε_{ττ}$ is seen to be very mild, once the $χ^2$ is marginalised over oscillation and NSI parameters. If the NSI are large enough, the event spectrum at ICAL is expected to be altered and this can be used to discover new physics. We calculate the lower limit on NSI parameters above which ICAL could discover NSI at a given C.L. from 10 years of data. If NSI were too small, the null signal at ICAL can constrain the NSI parameters. We give upper limits on the NSI parameters at any given C.L. that one is expected to put from 10 years of running of ICAL. Finally, we give C.L. contours in the NSI parameter space that is expected to be still allowed from 10 years of running of the experiment.

hep-ph↗