Investigation of thermoluminescence and photoluminescence properties of Tb, Eu, and Dy doped NaYF phosphors for dosimetric applications.

Hexagonal phase sodium yttrium fluoride activated with lanthanide ions; Tb, Eu and Dy doped NaYF phosphors were synthesized using a simplistic hydrothermal method. The photoluminescence studies demonstrated green, red and blue emission lines corresponding to D → F ( = 6, 5, 4, 3), D → F ( = 1, 2 and 4) and F to H ( = 15/2 and 13/2) transitions, which are characteristic of Tb, Eu and Dy ions, respectively. The as-synthesized samples were subjected to annealing at varying temperatures from 500 °C to 800 °C primarily for the optimization of the thermoluminescence glow curve.

Isomeric cross sections of the (n, α) reactions on the Zr, Nb and Mo isotopes measured for 13.73 MeV-14.77 MeV and estimated for 10 MeV-20 MeV neutron energies.

Isomeric cross sections for the Zr(n, α)Sr, Nb(n, α)Y and Mo(n, α)Zr reactions were measured at five neutron energies over the range 13.73 MeV-14.77 MeV using the activation technique in combination with high resolution γ-ray spectrometry.

Excitation functions for Bi reactions induced by threshold to 50 MeV energy alpha particles.

Excitation functions for Bi(α,2n)At, Bi(α,3n)At and Bi(α,4n)At reactions were calculated using TALYS-1.95 nuclear code from threshold to 50 MeV by invoking suitable options for level densities, nucleon-nucleus optical model potentials and alpha optical model potentials. Statistical factors were used to verify the quality of matching between theoretical model calculations and the experimental data from the EXFOR database.

The flux weighted cross sections of Hf(γ,γ')Hf and Hf(γ,x)Hf reactions at 8 MeV and 15 MeV bremsstrahlung end point energies.

For the hafnium element, the cross sections of Hf(γ,γ')Hf and Hf(γ,x)Hf reactions were measured at 8 MeV and 15 MeV bremsstrahlung end point energies respectively using activation method and off-line gamma-ray spectroscopy. The bremsstrahlung radiation spectra were generated by bombarding a 0.1 mm tungsten target with 8 MeV and 15 MeV electrons at 5 μA beam current and also theoretically simulated by GEANT4 computer code.

Analysis of neutron induced (n,γ) and (n,2n) reactions on Th from reaction threshold to 20 MeV.

Excitation functions for Th(n,γ) and Th(n,2n) reactions from reaction threshold to 20 MeV were calculated using TALYS-1.9 nuclear code by invoking suitable options for the level densities, optical model potentials, pre-equilibrium effects and γ-ray strength functions. In earlier studies, theoretical plots for Th(n,γ) and Th(n,2n) reaction cross-sections were obtained by using EMPIRE 3.

Cross sections for formation of Ce radioisotope through the Ce (n, 2n) reaction over 13.73-14.77 MeV neutrons.

Cross sections for the formation of metastable state of Ce through Ce(n, 2n)Ce reaction were measured at five neutron energies over 13.73-14.77 MeV range using the activation method and off-line gamma-ray spectrometric technique.

Monte Carlo based investigations of electron contamination from telecobalt unit head in build up region and its impact on surface dose.

A Telecobalt unit has wide range of applications in cancer treatments and is used widely in many countries all around the world. Estimation of surface dose in Cobalt-60 teletherapy machine becomes important since clinically useful photon beam consist of contaminated electrons during the patient treatment. EGSnrc along with the BEAMnrc user code was used to model the Theratron 780E telecobalt unit.

Design of 6Mev linear accelerator based pulsed thermal neutron source: FLUKA simulation and experiment.

The 6MeV LINAC based pulsed thermal neutron source has been designed for bulk materials analysis. The design was optimized by varying different parameters of the target and materials for each region using FLUKA code. The optimized design of thermal neutron source gives flux of 3×10(6)ncm(-2)s(-1) with more than 80% of thermal neutrons and neutron to gamma ratio was 1×10(4)ncm(-2)mR(-1).

Synthesis of gold and silver nanoparticles by electron irradiation at 5-15 keV energy.

Thin coatings (∼10 µm) made from a mixture of polyvinyl alcohol (PVA) and HAuCl(4) or PVA and AgNO(3) on quartz plates were irradiated with 5-15 keV electrons, at room temperature. The electron energy was varied from coating to coating in the range of 5-15 keV, but electron fluence was kept constant at ∼10(15) e cm(-2). Samples were characterized by the UV-vis, XRD, SEM and TEM techniques.