• A Kumar

Articles written in Pramana – Journal of Physics

• Development of a honeycomb gas proportional counter array for photon multiplicity measurements in high multiplicity environment

A novel gas-based detector using large arrays of honeycomb cells has been developed and tested for use as a pre-shower photon multiplicity detector (PMD) for STAR and ALICE experiments. The appropriate cell design was arrived at using GARFIELD simulations. Prototype chambers with cell dimensions corresponding to STAR and ALICE were fabricated and tested at CERN PS and SPS. The charged particle detection efficiency and the pre-shower characteristics have been studied using pion and electron beams.

• Dielectric properties of CdS nanoparticles synthesized by soft chemical route

CdS nanoparticles have been synthesized by a chemical reaction route using thiophenol as a capping agent. The frequency-dependent dielectric dispersion of cadmium sulphide (CdS) is investigated in the temperature range of 303–413 K and in a frequency range of 50 Hz–1 MHz by impedance spectroscopy. An analysis of the complex permittivity ($\varepsilon'$ and $\varepsilon''$ ) and loss tangent ($\tan \delta) with frequency is performed by assuming a distribution of relaxation times. The scaling behaviour of dielectric loss spectra suggests that the relaxation describes the same mechanism at various temperatures. The frequency-dependent electrical data are analysed in the framework of conductivity and modulus formalisms. The frequency-dependent conductivity spectra obey the power law. • Observation of Meyer–Neldel rule in thermally activated Poole–Frenkel photoconduction in a-Se70Te$_{30−x}$Cd$_{x}$thin films In the present paper, we report the compensation effect on photoconductivity of thin films of Se70Te$_{30−x}$Cd$_{x}$($x = 2, 4, 6$) alloys for high field conduction. Steady state photoconductivity measurements have been made in thin films for different electric fields. The photoconduction was found to be ohmic at low fields and Poole–Frenkel type at high fields. Meyer–Neldel rule (MN rule) for the pre-exponential factor$(\sigma_{\text{ph}})_{0}$and activation energy ($\Delta E_{\text{ph}}$) of photoconduction in thin films of Se70Te$_{30−x}$Cd$_{x}\$ is observed in the present study.

• Pramana – Journal of Physics

Volume 96, 2022
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