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

Applications of Hubble volume in atomic physics, nuclear physics, particle physics, quantum physics and cosmic physics

In this paper an attempt is made to emphasize the major shortcomings of standard cosmology. It can be suggested that, the current cosmological changes can be understood by studying the atom and the atomic nucleus through ground based experiments. If light is coming from the atoms of the gigantic galaxy, then redshift can be interpreted as an index of the galactic atomic 'light emission mechanism'. In no way it seems to be connected with 'galaxy receding'. With 'cosmological increasing (emitted) photon energy', observed cosmic redshift can be considered as a measure of the age dierence between our galaxy and any observed galaxy. If it is possible to show that, (from the observer) older galaxy's distance increases with its 'age', then 'galaxy receding' and 'accelerating universe' concepts can be put for a revision at fundamental level. At any given cosmic time, the product of 'critical density' and 'Hubble volume' gives a characteristic cosmic mass and it can be called as the 'Hubble mass'. Interesting thing is that, Schwarzschild radius of the 'Hubble mass' again matches with the 'Hubble length'. Most of the cosmologists believe that this is merely a coincidence. At any given cosmic time, 'Hubble length' can be considered as the gravitational or electromagnetic interaction range. If one is willing to think in this direction, by increasing the number of applications of Hubble mass and Hubble volume in other areas of fundamental physics like quantum physics, nuclear physics, atomic physics and particle physics - slowly and gradually - in a progressive way, concepts of 'Black hole Cosmology' can be strengthened and can also be confirmed. 

Keywords:- Hubble length, Hubble volume, Hubble mass, Cosmic redshift, CMBR energy density, Reduced Planck's constant, rms radius of proton. 

Authors:- U. V. S. Seshavatharam 
Honorary faculty, I-SERVE, Alakapuri, Hyderabad-35, AP, India. 
Prof. S. Lakshminarayana 
Dept. of Nuclear Physics, Andhra University, Visakhapatnam-03, AP,India