Sunil Kumar | Chitkara University (original) (raw)
Papers by Sunil Kumar
Evidence is provided for radiative resonant energy transfer (RRET) from bulk plasmons to discrete... more Evidence is provided for radiative resonant energy transfer (RRET) from bulk plasmons to discrete states for the first time. The difference of the excitation mechanisms of the 1s2s 3 S 1 and 1s2p 3 P o 2 states in He-like Ti ions on target nuclear charge have been studied by the beam-two-foil technique. We observed that the 1s2s 3 S 1 states are mostly populated with an aluminum target where as the 1s2p 3 P o 2 states with a carbon target. The 1s2s 3 S 1 states produced with a carbon target are further excited to 1s2p 3 P o 2 state, but this type of excitation does not occur with an aluminum target. This excitation mechanism is attributed to resonant energy transfer from bulk plasmons in the carbon target. Furthermore, the resonant process is confirmed by observation that the 1s2s 3 S 1 states populate more than the 1s2p 3 P o 2 states with He-like V, Fe and Ni ions even with carbon targets.
The elemental concentration of uranium in the samples collected from the ground water and the can... more The elemental concentration of uranium in the samples collected from the ground water and the canal water in the Bathinda district of Punjab state, India, have been investigated using X-ray fluorescence technique. The residues obtained after drying the water samples were analysed using the energy dispersive X-ray fluorescence spectrometer consisting of Mo-anode X-ray tube equipped with selective absorbers as an excitation source and an Si(Li) detector. The uranium concentration values in significant fraction of the shallow ground water samples from the hand pumps is found to be above the permissible level of 15 ppb recommended by World Health Organisation for the drinking water, and its values in the canal water samples are below 5 ppb. To investigate the flyash from the coal-fired thermal power plants as a possible source of ground water contamination, the water samples collected from the surroundings of the power plants and the flyash samples were also analyzed. The results rule out flyash as a source of uranium contamination. Agrochemical processes occurring in the calcareous soils in the region are the favoured potential source of uranium contamination of the ground water.
Pramana, Jan 1, 2011
The near-edge processes, such as X-ray absorption fine structure (XAFS) andresonant Raman scatter... more The near-edge processes, such as X-ray absorption fine structure (XAFS) andresonant Raman scattering (RRS), are not incorporated in the available theoretical attenuation coefficients, which are known to be reliable at energies away from the shell/subshell ionization thresholds of the attenuator element. Theoretical coefficients are generally used to estimate matrix corrections in routine quantitative elemental analysis based on various X-ray emission techniques. A tabulation of characteristic X-ray energies across the periodic table is provided where those X-rays are expected to alter the attenuation coefficients due to XAFS from a particular shell/subshell of the attenuator element. The influence of XAFS to the attenuation coefficient depends upon the atomic environment and the photoelectron wave vector, i.e., difference in energies of incident X-ray and the shell/subshell ionization threshold of the attenuator element. Further, the XAFS at a shell/subshell will significantly alter the total attenuation coefficient if the jump ratio at that shell/subshell is large, e.g., the K shell, L 3 subshell and M 5 subshell. The tabulations can be considered as guidelines so as to know what can be expected due to XAFS in typical photon-induced X-ray emission spectrometry.
Nuclear Instruments and …, Jan 1, 2010
A tabulation of characteristic X-ray energies across the periodic table are provided where those ... more A tabulation of characteristic X-ray energies across the periodic table are provided where those X-rays are expected to result in a significant fractional resonant Raman scattering (RRS) contribution to the X-ray attenuation from a particular shell/subshell of the same or ...
Journal of Applied …, Jan 1, 2009
... The mass-attenuation coefficients for the soft x rays with energies varying 14502350 eV have... more ... The mass-attenuation coefficients for the soft x rays with energies varying 14502350 eV have been mea-sured for 73Ta and 74W by Levine et al.23 Eisa et al.24 studied the near edge mass-attenuation coefficients of elements with 22Z 30 using synchrotron radiation facility. ...
… Journal of PIXE- …, Jan 1, 2011
ABSTRACT The present study was carried out with the aim to determine if, orthodontic patients acc... more ABSTRACT The present study was carried out with the aim to determine if, orthodontic patients accumulate measurable concentration of Ni in blood or not, since the recent evidences shows the allergenic actions of Ni in various forms and orthodontic appliances have been reported to produce Ni allergy. In our experiment, the blood samples were taken before the insertion of appliance and at an interval of 6 months over a total time period of 18 months (four sets) from the Oral Health Department of Post Graduate Institute of Medical Education & Research (PGIMER), Chandigarh, India. In all the four sets of blood samples the common trace elements were detected viz. S, K, Ca, Cr, Fe, Cu, Zn and Br. Our result shows the complete absence of Ni in the blood.
Nuclear Instruments and …, Jan 1, 2010
Attenuation of the characteristic K X-rays in the 48Cd, 50Sn, 52Te, 64Gd, 65Tb, 66Dy, 68Er, 74Ta,... more Attenuation of the characteristic K X-rays in the 48Cd, 50Sn, 52Te, 64Gd, 65Tb, 66Dy, 68Er, 74Ta, 75Re, 79Au, 82Pb and 83Bi elements have been measured with especial emphasis for the X-ray energies (Ein) in the region of respective K-shell/Li subshell (i = 1, 2, 3) ionization threshold (BK/BLi). The characteristic X-rays were obtained from different fluorescent target elements excited by the X-rays and γ-rays emitted from the 55Fe and 241Am radioisotopes, respectively. The measurements were performed using an energy-dispersive detection set up involving a low-energy Ge detector. The measured attenuation coefficients for the X-rays with energies away from ionization thresholds of the attenuator element are found to be in good agreement with the available theoretical coefficients, which incorporate contributions of the photoionization, and the Rayleigh and Compton scattering processes. However, the measured attenuation coefficients are found to deviate significantly from the theoretical values for the X-rays with energies in vicinity of BK/Li. The observed alteration is attributed to the X-ray Absorption Fine Structure (XAFS) for negative BK/Li − Ein values, and the K-shell/Li subshell resonant Raman scattering (RRS) process for positive BK/Li − Ein values. Systematic of the K-shell/Li subshell RRS contribution to attenuation of the X-rays are discussed in terms of the respective oscillator density and fraction of electrons available in the K-shell/Li subshell Lorentzian profile of the attenuation element below Ein.
Evidence is provided for radiative resonant energy transfer (RRET) from bulk plasmons to discrete... more Evidence is provided for radiative resonant energy transfer (RRET) from bulk plasmons to discrete states for the first time. The difference of the excitation mechanisms of the 1s2s 3 S 1 and 1s2p 3 P o 2 states in He-like Ti ions on target nuclear charge have been studied by the beam-two-foil technique. We observed that the 1s2s 3 S 1 states are mostly populated with an aluminum target where as the 1s2p 3 P o 2 states with a carbon target. The 1s2s 3 S 1 states produced with a carbon target are further excited to 1s2p 3 P o 2 state, but this type of excitation does not occur with an aluminum target. This excitation mechanism is attributed to resonant energy transfer from bulk plasmons in the carbon target. Furthermore, the resonant process is confirmed by observation that the 1s2s 3 S 1 states populate more than the 1s2p 3 P o 2 states with He-like V, Fe and Ni ions even with carbon targets.
The elemental concentration of uranium in the samples collected from the ground water and the can... more The elemental concentration of uranium in the samples collected from the ground water and the canal water in the Bathinda district of Punjab state, India, have been investigated using X-ray fluorescence technique. The residues obtained after drying the water samples were analysed using the energy dispersive X-ray fluorescence spectrometer consisting of Mo-anode X-ray tube equipped with selective absorbers as an excitation source and an Si(Li) detector. The uranium concentration values in significant fraction of the shallow ground water samples from the hand pumps is found to be above the permissible level of 15 ppb recommended by World Health Organisation for the drinking water, and its values in the canal water samples are below 5 ppb. To investigate the flyash from the coal-fired thermal power plants as a possible source of ground water contamination, the water samples collected from the surroundings of the power plants and the flyash samples were also analyzed. The results rule out flyash as a source of uranium contamination. Agrochemical processes occurring in the calcareous soils in the region are the favoured potential source of uranium contamination of the ground water.
Pramana, Jan 1, 2011
The near-edge processes, such as X-ray absorption fine structure (XAFS) andresonant Raman scatter... more The near-edge processes, such as X-ray absorption fine structure (XAFS) andresonant Raman scattering (RRS), are not incorporated in the available theoretical attenuation coefficients, which are known to be reliable at energies away from the shell/subshell ionization thresholds of the attenuator element. Theoretical coefficients are generally used to estimate matrix corrections in routine quantitative elemental analysis based on various X-ray emission techniques. A tabulation of characteristic X-ray energies across the periodic table is provided where those X-rays are expected to alter the attenuation coefficients due to XAFS from a particular shell/subshell of the attenuator element. The influence of XAFS to the attenuation coefficient depends upon the atomic environment and the photoelectron wave vector, i.e., difference in energies of incident X-ray and the shell/subshell ionization threshold of the attenuator element. Further, the XAFS at a shell/subshell will significantly alter the total attenuation coefficient if the jump ratio at that shell/subshell is large, e.g., the K shell, L 3 subshell and M 5 subshell. The tabulations can be considered as guidelines so as to know what can be expected due to XAFS in typical photon-induced X-ray emission spectrometry.
Nuclear Instruments and …, Jan 1, 2010
A tabulation of characteristic X-ray energies across the periodic table are provided where those ... more A tabulation of characteristic X-ray energies across the periodic table are provided where those X-rays are expected to result in a significant fractional resonant Raman scattering (RRS) contribution to the X-ray attenuation from a particular shell/subshell of the same or ...
Journal of Applied …, Jan 1, 2009
... The mass-attenuation coefficients for the soft x rays with energies varying 14502350 eV have... more ... The mass-attenuation coefficients for the soft x rays with energies varying 14502350 eV have been mea-sured for 73Ta and 74W by Levine et al.23 Eisa et al.24 studied the near edge mass-attenuation coefficients of elements with 22Z 30 using synchrotron radiation facility. ...
… Journal of PIXE- …, Jan 1, 2011
ABSTRACT The present study was carried out with the aim to determine if, orthodontic patients acc... more ABSTRACT The present study was carried out with the aim to determine if, orthodontic patients accumulate measurable concentration of Ni in blood or not, since the recent evidences shows the allergenic actions of Ni in various forms and orthodontic appliances have been reported to produce Ni allergy. In our experiment, the blood samples were taken before the insertion of appliance and at an interval of 6 months over a total time period of 18 months (four sets) from the Oral Health Department of Post Graduate Institute of Medical Education & Research (PGIMER), Chandigarh, India. In all the four sets of blood samples the common trace elements were detected viz. S, K, Ca, Cr, Fe, Cu, Zn and Br. Our result shows the complete absence of Ni in the blood.
Nuclear Instruments and …, Jan 1, 2010
Attenuation of the characteristic K X-rays in the 48Cd, 50Sn, 52Te, 64Gd, 65Tb, 66Dy, 68Er, 74Ta,... more Attenuation of the characteristic K X-rays in the 48Cd, 50Sn, 52Te, 64Gd, 65Tb, 66Dy, 68Er, 74Ta, 75Re, 79Au, 82Pb and 83Bi elements have been measured with especial emphasis for the X-ray energies (Ein) in the region of respective K-shell/Li subshell (i = 1, 2, 3) ionization threshold (BK/BLi). The characteristic X-rays were obtained from different fluorescent target elements excited by the X-rays and γ-rays emitted from the 55Fe and 241Am radioisotopes, respectively. The measurements were performed using an energy-dispersive detection set up involving a low-energy Ge detector. The measured attenuation coefficients for the X-rays with energies away from ionization thresholds of the attenuator element are found to be in good agreement with the available theoretical coefficients, which incorporate contributions of the photoionization, and the Rayleigh and Compton scattering processes. However, the measured attenuation coefficients are found to deviate significantly from the theoretical values for the X-rays with energies in vicinity of BK/Li. The observed alteration is attributed to the X-ray Absorption Fine Structure (XAFS) for negative BK/Li − Ein values, and the K-shell/Li subshell resonant Raman scattering (RRS) process for positive BK/Li − Ein values. Systematic of the K-shell/Li subshell RRS contribution to attenuation of the X-rays are discussed in terms of the respective oscillator density and fraction of electrons available in the K-shell/Li subshell Lorentzian profile of the attenuation element below Ein.