Ashok Kumar
Articles written in Pramana – Journal of Physics
Volume 10 Issue 1 January 1978 pp 63-73 Atomic Physics
Elastic scattering of electrons by argon atoms
The partial wave method with a central potential has been applied to investigate the elastic scattering of electrons by the argon atoms in the intermediate energy range (100 eV − 1 keV). The central potential includes the effects of the static field, exchange and polarization. The results are in good accord with recent experimental data.
Volume 10 Issue 4 April 1978 pp 409-412 Solids
Magnetic susceptibility of heavy rare-earth sesquioxides
H B Lal Virendra Pratap Ashok Kumar
Measurement of magnetic susceptibility of the powder samples of heavy rare-earth (Tb, Dy, Ho, Er, Tm and Yb) sesquioxides have been reported in the temperature range 300 to 900 K. Curie-Weiss law behaviour has been observed for all samples. The Curie constant, the paramagnetic Curie temperature and the magneton number for magnetic ions in each material have also been evaluated.
Volume 14 Issue 3 March 1980 pp 223-232 Nuclear Physics
Back-bending in^{182,184,186}osmium
The high spin yrast states upto
Volume 15 Issue 5 November 1980 pp 435-447 Nuclear And Particle Physics
High spin yrast states in even platinum isotopes
The high spin yrast states up to
Volume 19 Issue 2 August 1982 pp 189-202 Nuclear And Particle Physics
The quadrupole plus pairing interaction model in large configuration space for W, Os and Pt nuclei
The equilibrium deformations of tungsten, osmium and platinum nuclei are studied with the self-consistent quadrupole plus pairing interaction model by considering all the nucleons in nucleus explicitly. It is shown that similar results can be obtained by performing calculations with or without the assumption of an inert core. The only difference is in the strength of the quadrupole and pairing interactions to be employed in the respective calculations. The experimental static quadrupole moments and the
Volume 35 Issue 5 November 1990 pp 449-459
Elastic scattering of
A relatively simple procedure using nuclear interaction calculated microscopically from two-nucleon potential employing equivalence of resonating group method and generator coordinate method has been used to calculate the differential cross-sections (DCS) for
Volume 43 Issue 4 October 1994 pp 339-351
Level structures in the odd-odd nucleus^{180}Re
Ashok Kumar Jain Prakash C Sood Raymond K Sheline
Experimental data on energy levels of the odd-odd deformed nucleus^{180}Re obtained from radioactive-decay and heavy-ion reaction studies are analysed to deduce spin-parity and configuration assignments for the six observed rotational bands based on the selection rules for fast beta transitions, criteria for the relative-energy ordering of the triplet and singlet bandheads, two-particle-plus-rotor model calculations including Coriolis mixing, rotational energy systematics involving staggering features, and considerations of gyromagnetic ratios, signature splittings and rotational band alignments.
Volume 53 Issue 2 August 1999 pp 243-251
Trace formula for level density of a spherical billiard
Sham Sunder Malik Manisha Dudeja Ashok Kumar Jain
A trace formula for the oscillating part of the level density for a spherical billiard has been obtained in spherical polar coordinates. The Jacobian of stability and the length of the orbits are obtained from the classical mechanics of the problem. The same formula is applicable to both the planar and the diametric orbits. Numerical results have been obtained with this formula and compared with the results from exact quantum theory, EBK quantization, and Balian and Bloch.
Volume 57 Issue 2-3 August 2001 pp 611-622
Magnetic rotation and chiral symmetry breaking
The deformed mean field of nuclei exhibits various geometrical and dynamical symmetries which manifest themselves as various types of rotational and decay patterns. Most of the symmetry operations considered so far have been defined for a situation wherein the angular momentum coincides with one of the principal axes and the principal axis cranking may be invoked. New possibilities arise with the observation of rotational features in weakly deformed nuclei and now interpreted as magnetic rotational bands. More than 120 MR bands have now been identified by filtering the existing data. We present a brief overview of these bands. The total angular momentum vector in such bands is tilted away from the principal axes. Such a situation gives rise to several new possibilities including breaking of chiral symmetry as discussed recently by Frauendorf. We present the outcome of such symmetries and their possible experimental verification. Some possible examples of chiral bands are presented.
Volume 78 Issue 3 March 2012 pp 493-498 Brief Report
Measurement of peak ﬂuence of neutron beams using Bi-ﬁssion detectors
R K Jain Ashok Kumar N L Singh L Tommasino B K Singh
Fission fragments and other charged particles leave tracks of permanent damage in most of the insulating solids. Damage track detectors are useful for personal dosimeters and for ﬂux/dose determination of high-energy particles from accelerators or cosmic rays. A detector that has its principal response at nucleon energy above 50 MeV is provided by the ﬁssion of Bi-209. Neutrons produce the largest percentage of hadron dose in most high-energy radiation ﬁelds. In these ﬁelds, the neutron spectrum is typically formed by low-energy neutrons (evaporation spectrum) and high-energy neutrons (knock-on spectrum). We used Bi-ﬁssion detectors to measure neutron peak ﬂuence and compared the result with the calculated value of neutron peak ﬂuence. For the exposure to 100 MeV we have used the iThemba Facility in South Africa.
Volume 79 Issue 5 November 2012 pp 1243-1246 Poster Presentations
Main injector particle production experiment at Fermilab
Sonam Mahajan Ashok Kumar Rajendran Raja
The main injector particle production (MIPP) experiment at Fermilab uses particle beams of charged pions, kaons, proton and antiproton with beam momenta of 5–90 GeV/c to measure particle production cross-sections of various nuclei including liquid hydrogen, MINOS target and thin targets of beryllium, carbon, bismuth and uranium. The physics motivation to perform such cross-section measurements is described here. Recent results on the analysis of NuMI target and forward neutron cross-sections are presented here. Preliminary cross-section measurements for 58 GeV/c proton on liquid hydrogen target are also presented. A new method is described to correct for low multiplicity inefficiencies in the trigger using KNO scaling.
Volume 84 Issue 4 April 2015 pp 591-608
Ashwini Kumar A Prakash Ashok Kumar R K Jain B K Singh
An analysis of the data based on 924 inelastic interaction events induced by ^{28} Si nuclei in a nuclear emulsion is presented. The nuclear fragmentation process is studied by analysing the total charge (𝑄) distribution of the projectile spectators for different emulsion target groups along with the comparison of Monte Carlo Glauber model results. Probability distributions for total disintegrated events as a function of different projectile masses are shown and compared with cascade evaporation model results at same energy per nucleon. Further, mean multiplicities of different charged secondaries for different classes of events are presented and for each event, variation of mean multiplicities as a function of total charge (𝑄) is also presented. The pseudorapidity distributions and normalized pseudorapidity distributions of the produced charged particles in nucleus–nucleus collisions at 3.7 A GeV are analysed for total disintegration (TD) as well as minimum-bias events.
Volume 88 Issue 5 May 2017 Article ID 0079 Research Article
Physics potential of the ICAL detector at the India-based Neutrino Observatory (INO)
A KUMAR A M VINOD KUMAR ABHIK JASH AJIT K MOHANTY ALEENA CHACKO ALI AJMI AMBAR GHOSAL AMINA KHATUN AMITAVA RAYCHAUDHURI AMOL DIGHE ANIMESH CHATTERJEE ANKIT GAUR ANUSHREE GHOSH ASHOK KUMAR ASMITA REDIJ B SATYANARAYANA B S ACHARYA BRAJESH C CHOUDHARY C RANGANATHAIAH C D RAVIKUMAR CHANDAN GUPTA D INDUMATHI DALJEET KAUR DEBASISH MAJUMDAR DEEPAK SAMUEL DEEPAK TIWARI G RAJASEKARAN GAUTAM GANGOPADHYAY GOBINDA MAJUMDER H B RAVIKUMAR J B SINGH J S SHAHI JAMES LIBBY JYOTSNA SINGH K RAVEENDRABABU K K MEGHNA K R REBIN KAMALESH KAR KOLAHAL BHATTACHARYA LALIT M PANT M SAJJAD ATHAR M V N MURTHY MANZOOR A MALIK MD NAIMUDDIN MOHAMMAD SALIM MONOJIT GHOSH MOON MOON DEVI NABA K MONDAL NAYANA MAJUMDAR NITA SINHA NITALI DASH POMITA GHOSHAL POONAM MEHTA PRAFULLA BEHERA R KANISHKA RAJ GANDHI RAJESH GANAI RASHID HASAN S KRISHNAVENI S M LAKSHMI S K SINGH S S R INBANATHAN S UMA SANKAR SADIQ JAFER SAIKAT BISWAS SANJEEV KUMAR SANJIB KUMAR AGARWALLA SANDHYA CHOUBEY SATYAJIT SAHA SHAKEEL AHMED SHIBA PRASAD BEHERA SRUBABATI GOSWAMI SUBHASIS CHATTOPADHYAY SUDEB BHATTACHARYA SUDESHNA BANERJEE SUDESHNA DASGUPTA SUMANTA PAL SUPRATIK MUKHOPADHYAY SUSHANT RAUT SUVENDU BOSE SWAPNA MAHAPATRA TAPASI GHOSH TARAK THAKORE V K S KASHYAP V S SUBRAHMANYAM VENKTESH SINGH VINAY B CHANDRATRE VIPIN BHATNAGAR VIVEK M DATAR WASEEM BARI Y P VIYOGI
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 andpath 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 toaddress 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 responseof 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. Itscharge 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.
Volume 89 Issue 5 November 2017 Article ID 0075 Research Article
BHOOMIKA MAHESHWARI SWATI GARG ASHOK KUMAR JAIN
We show for the first time that the generalized seniority scheme explains reasonably well the $B(E3)$ systematics for the $(0^{+} → 3^{−}_{1})$ transitions in the Sn isotopes, which are odd-tensor $E3$ transitions connecting different seniority states $(\Delta\upsilon = 2)$. Additionally, we also present large scale shell model (LSSM) calculations to support our interpretation. The generalized seniority scheme points to the octupole character of these 3− states in Sn isotopes.
Volume 92 Issue 3 March 2019 Article ID 0035 Research Article
Test of isospin conservation in thermal neutron-induced fission of $^{245}Cm$
We have recently shown that the general trends of partition-wise fission fragment mass distribution in heavy-ion-induced compound nuclear (CN) fission of heavy nuclei can be reproduced reasonably well by using theconcept of isospin conservation, hence providing a direct evidence of isospin conservation in neutron-rich systems [Jain
Volume 94 All articles Published: 7 October 2020 Article ID 0142 Research Article
Effect of point/line heat source and Hall current on free convective flow between two vertical walls
NAVEEN DWIVEDI ASHOK KUMAR SINGH
The influence of a point heat source and Hall current on the laminar hydromagnetic free convective flow of an incompressible and electrically conducting viscous liquid between two vertical walls has been studied. A wavelet function is utilised to mathematically formulate the point or line heat source. The incidental equations on the flow have been processed subject to the Boussinesq approximation. A unified analytical solution of basic equations like thermal energy and momentum has been derived by employing Laplace transform technique. The impacts of the pertinent physical parameters, such as Hall parameter, magnetic field and point heat source, on the velocity field are explained graphically. The valuable result from the investigation is that an increase in the length of the point heat source leads to the enhancement of the velocity profiles. Moreover, it is noticeable that an enhancement of Hall current has a direct connection with the primary factor of the volumetric flow rate and skin friction.
Volume 96 All articles Published: 16 May 2022 Article ID 0099 Research Article
NAVEEN DWIVEDI ASHOK KUMAR SINGH PALLATH CHANDRAN NIRMAL C SACHETI
This theoretical paper deals with a fully developed free convective flow of an incompressible viscous and electrically conducting fluid in an infinitely long rigid vertical channel in the presence of an externally applied magnetic field. By retaining the induced magnetic field, we have carried out a detailed analysis of the field equations and obtained a host of interesting results corresponding to both open-circuit and short-circuit arrangements. The governing PDEs, which under the chosen physical configuration get transformed to a set of ordinary differential equations together with appropriate boundary conditions, have further been subjected to non-dimensionalisation. Using the theory of simultaneous ordinary differential equations, the analytical solutions for velocity, temperature field and induced magnetic field were obtained. These solutions were used to obtain important quantities of engineering interest such as current density, wall skin friction and volumetric flux for both open and short circuits.The effect of Hartmann number on the velocity, induced magnetic field and induced current density were shown quite extensively. Furthermore, the results for the symmetric and asymmetric heating of the vertical walls of the channelfor open- and short-circuit arrangements were compared. It is found that for the open-circuit arrangement, the velocity, induced current density and induced magnetic field are higher than that for the short-circuit arrangement.
Volume 96 All articles Published: 10 August 2022 Article ID 0148 Research Article
UV effect on etching parameters and activation energy of CR-39 plastic detector
An investigation has been made relating the effect of UV radiations on etching parameters and activation energy of CR-39 (solid-state nuclear track detectors, (SSNTDs)).
Corresponding changes in bulk etch rate (BER) (
Volume 97, 2023
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