Extensions of Natural Radioactivity to 4th-Type and of the Periodic Table to Super-heavy Nuclei: Contribution of Raj K Gupta to Cold Nuclear Phenomena

We have studied here the contribution of Indian Scientists associated with Prof. Raj K. Gupta to cold nuclear phenomena during the last almost four decades, which led to the discovery of fourth kind of natural radioactivity (also known as Cluster Radioactivity, CR) and to the extension of periodic table to super heavy nuclei. It is exclusively pointed out how the Quantum Mechanical Fragmentation Theory (QMFT) advanced by Prof. Raj K. Gupta and Collaborators led to the discovery of unique phenomenon of CR along with the predictions leading to the synthesis of super heavy elements. We have also mentioned the development of dynamical theories based on QMFT, the Preformed Cluster Model(PCM) and the dynamical cluster-decay model (DCM), to study the ground and excited state decays of nuclei, respectively, by Gupta and Collaborators. It is matter of great honor and pride for us to bring out this study to enthuse the young researchers to come up with novel ideas and have inspiration from the scientific contributions of Prof. Raj K. Gupta who is coincidentally celebrating his platinum jubilee birthday anniversary this year. 

Keywords:- Cluster model, low energy, super heavy elements, alpha decay 

Authors:- BirBikram Singh

Department of Physics, Sri Guru Granth Sahib World University, Fatehgarh Sahib-140406, INDIA
Email:-birbikram.singh@gmail.com

Manoj K. Sharma
School of Physics and Materials Science, Thapar University, Patiala-147004, INDIA

S. K. Patra 
Institute of Physics, Sachivalaya Marg, Bhubaneswar-751005, INDIA

Partial as Well as Total Photon Interaction Effective Atomic Numbers for Some Concretes

Photon interaction effective atomic number (Z ) for partial as eff well as total photon interaction processes has been used computed using logarithmic interpolation method for seven different concretes viz. (i) Ordinary, (ii) Hematite - Serpentine, (iii) Ilmenite - Limonite, (iv) Basalt - magnetite, (v) Ilmenite, (vi) Steel - scrap and (vii) Steel - magnetite concrete in the wide energy range from 10.0 keV to 100 GeV. It has been concluded that this method has an advantage over the atomic to electronic cross-section ratio method especially for mixtures in the intermediate energy level. However, due to lack of experimental data in the higher energy region, it is dificult to discuss, its validity in these energy regions. 

Keywords:- Photon interactions, mass attenuation coeficient, effective atomic number, concrete
.Authors:- Tejbir Singh 

Department of Physics, Sri Guru Granth Sahib World University, Fatehgarh Sahib - 140406.
Parjit S. Singh 

Department of Physics, Punjabi University, Patiala-147002, Punjab, India.

Alignment Studies for Tungsten Near L3 Sub-Shell Threshold Via Theoretical, Experimental and Empirical Methods

Alignment studies are made for tungsten near L3 sub-shell hreshold using theoretical, experimental and empirical approaches. Experimentally to measure alignment parameter, the angular distribution of L x-rays of tungsten (W-74) is measured in the angular range 0 to 120, where maximum anisotropy is expected. The experimental measurements are performed in XRF laboratories of Raja Ramanna Center for Advanced Technology (RRCAT), Indore, India using a three-dimensional double relection set-up. The weighted average of alignment values with 10% error comes 0.155 0.009. Theoretically, the value of alignment parameter A is calculated using non-relativistic dipole approximation in a point 20 Coulomb potential and is found 0.151 at L3 threshold energy (10.676 keV). For empirical A evaluations, IGELCS interpolated experimental 20 LXRF cross-section *Lg (g = , ) values of Mann et al with 8% reported errors are used along with the radiative decay rates. The comparison among heoretical, experimental and empirical values are similar and values being >0.1 at L3 threshold energy are certainly higher than the 5 to 8 percent uncertainties quoted in earlier experimental results. 

Keywords:- Alignment, cross-section, anisotropy, angular distribution and x-ray luorescence 
Authors:- Ajay Sharma 
Physics Department, Chitkara University, Himachal Pradesh-174103-INDIA 
Raj Mittal 

Nuclear science Laboratories, Physics department, Punjabi University Patiala-147002-INDIA

Third harmonic generation of a short pulse laser in a tunnel ionizing plasma: Effect of self-defocusing

Third harmonic generation of a Gaussian short pulse laser in a tunnel ionizing plasma is investigated. A Gaussian short pulse laser propagating through a tunnel ionizing plasma generates third harmonic wave. Inhomogeneity of the electric ield along the wavefront of the fundamental laser pulse causes more ionization along the axis of propagation while less ionization off axis, leading to strong density gradient with its maximum on the axis of propagation. The medium acts like a diverging lens and pulse defocuses strongly. The normalized third harmonic amplitude varies periodically with the distance with successive maxima acquiring lower value. The self-defocusing of the fundamental laser pulse decays the intensity of the third harmonic pulse. 

Keywords:- third harmonic generation, self defocusing, laser, plasma. 
Authors:- Niti Kant

Department of Physics, Lovely Professional University, Phagwara-144411, Punjab, India.

Elemental analysis of nanomaterial using photon-atom interaction based EDXRF technique

Abstract Presence of trace amount of foreign impurities (both metallic and non-metallic) in standard salts used for sample preparation and during the synthesis process can alter the physical and chemical behavior of the pure and doped nano-materials. Therefore, it becomes important to determine concentration of various elements present in synthesized nano-material sample. In present work, the elemental and compositional analysis of nano-materials synthesized using various methods has been performed using photon-atom interaction based energy dispersive x-ray luorescence (EDXRF) technique. This technique due to its multielement analytical capability, lower detection limit, capability to analyze metals and non-metals alike and almost no sample preparation requirements can be utilized for analysis of nano-materials. The EDXRF spectrometer involves a 2.4 kW Mo anode x-ray tube (Pananalytic, Netherland) equipped with selective absorbers as an excitation source and an LEGe detector (FWHM = 150 eV at 5.895 keV, Canberra, US) coupled with PC based multichannel analyzer used to collect the luorescent x-ray spectra. The analytical results showed good agreements with the expected values calculated on the basis of the precursor used in preparation of nano-materials. 

Authors:- Sanjeev Kumar

G.G.D.S.D. College Sector-32, Chandigarh
Arun Kumar 
Department of Physics, Panjab University, Chandigarh
Mansi Chitkara 
Nanomaterials Research Laboratory, Chitkara University, Rajpura 140401, Punjab, India
I.S. Snadhu 
Nanomaterials Research Laboratory, Chitkara University, Rajpura 140401, Punjab, IndiaDevinder Mehta
Department of Physics, Panjab University, Chandigarh