arXiv subjects

Mohit Tyagi

Publications and source records attributed to Mohit Tyagi.

3 recordsLinked to original sources

arXiv2024

Cosmic observation of a model in the horizon of $ f(Q, C) $-gravity

In this work, we developed a cosmological model in $ f(Q, C) $ gravity within the framework of symmetric teleparallel geometry. In addition to the non-metricity scalar $Q $, our formulation includes the boundary term $ C $, which accounts for its deviation from the standard Levi-Civita Ricci scalar $ R^* $ in the Lagrangian. We derived the field equations for the metric and affine connection, employed them within a cosmological setting, and a vanishing affine connection to derive modified Friedmann equations. We used the latest observational dataset OHD in the redshift range $ z \in [0, 2.36]$, Pantheon + SH0ES in the redshift range $ z \in (0.01, 2.26)$, BAO, and the joint datasets OHD + Pantheon + SH0ES and OHD + Pantheon + SH0ES + BAO to constrain the parameters of our model by employing Markov Chain Monte Carlo (MCMC) method to minimize the $χ^2$ term. Using the constrained free model parameters, we carefully analyzed the behavior of different physical parameters and verified that the model transits from deceleration to acceleration. Finally, we observed that the model demonstrates an expanding quintessence dark energy model and converges to the $ Λ$CDM in later times.

gr-qc↗

arXiv2023

Thickness Dependent Sensitivity of GAGG:Ce Scintillation detectors for Thermal Neutrons: GEANT4 Simulations and Experimental Measurements

In the present work, we report extensive GEANT4 simulations in order to study the dependence of sensitivity of GAGG:Ce scintillation crystal based detector on thickness of the crystal. All the simulations are made considering a thermalised Am-Be neutron source. The simulations are validated, qualitatively and quantitatively, by comparing the simulated energy spectra and sensitivity values with those obtained from experimental measurements carried out using two different thicknesses of the crystal from our own experiment (0.5mm and 3mm) and validated with three other thicknesses (0.01mm, 0.1 mm and 1 mm) from literature. In this study, we define sensitivity of GAGG:Ce as the ratio of area under 77 keV sum peak to 45 keV peak. The present studies clearly confirm that, while it requires about 0.1 mm thickness for the GAGG:Ce crystal to fully absorb thermal neutrons, it requires about 3 mm to fully absorb the thermal neutron induced events. Further, we propose an equation, that can be used to estimate the thickness of the GAGG:Ce crystal directly from the observed sensitivity of the GAGG:Ce crystal. This equation could be very useful for the neutron imaging community for medical and space applications, as well as for manufactures of cameras meant for nuclear security purposes.

physics.ins-det↗

arXiv2023

Neutron-Gamma Pulse Shape Discrimination for Organic Scintillation Detector using 2D CNN based Image Classification

This study shows an implementation of neutron-gamma pulse shape discrimination (PSD) using a two-dimensional convolutional neural network. The inputs to the network are snapshots of the unprocessed, digitized signals from a BC501A detector. By exposing a BC501A detector to a Cf-252 source, neutron and gamma signals were collected to create a training dataset. The realistic datasets were created using a data-driven approach for labeling the digitized signals, having classified snapshots of neutron and gamma pulses. Our algorithm was able to successfully differentiate neutrons and gammas with similar accuracy as the CI approach. Additionally, the independent dataset accuracy for our suggested 2D CNN-based PSD approach is 99%. In contrast to the traditional charge integration method, our suggested algorithm with data augmentation, is capable of extracting features from snapshots of the raw data based on the signal structures, making it computationally more efficient and also appropriate for other types of neutron detectors.

physics.ins-det↗