Thermoluminescence studies of Si+8 ion irradiated kyanite

Thermoluminescence (TL) of natural kyanite single crystals bombarded with 100 MeVSi+8 ions with fluences in the range 1Ã10 11-5Ã1013 ions/cm2 has been studied at room temperature (RT). Two TL glows, a medium one at â¼ 445 K and another intense one at â¼ 550 K are recorded in single crystals of kyanite. However, in the case of pelletized samples, similar TL glows but with peaks at â¼ 475 and 615 K, respectively, are recorded at a warming rate of 20 K/min. It is found that as the fluence of Si+8 ion increases, the TL intensity increases. It is also found that the characteristic TL glow peaks appear at higher temperature side in pelletized kyanite than those in crystalline ones, however, the glow peak temperatures remain steady in a given system irrespective of the ion dose. The enhancement in TL intensity and shifting of TL glow peaks to higher temperature side in pelletized kyanite samples are attributed to the particle nature of the phosphor and/or pressure-induced defects in the phosphor. © 2003 Published by Elsevier Ltd

Ionoluminescence and photoluminescence in swift heavy ion-irradiated Al2SiO5

Ionoluminescence (IL) and photoluminescence (PL) of aluminum silicates irradiated with 100 MeV swift Ni+8 ions with fluences in the range 7.5à 1010-1.0Ã1014 ions/cm2 have been studied. A pair of IL bands with peaks at â¼ 775 and 875 nm are recorded in both natural crystalline and pelletized kyanite samples. And, a pair of sharp as well as strong PL emission bands with peaks at â¼ 688.7 and 705.9 nm along with a broad emission band in the region 710-900 nm are recorded in these samples with an excitation of 442 nm laser beam. It is found that both IL and PL intensities decrease with increase of ion fluence. The decrease of IL is attributed to amorphization of the material. © 2003 Published by Elsevier Ltd

Photoluminescence studies in swift heavy ion bombarded mullite

Photoluminescence (PL) of pelletized mullite samples irradiated with 100 MeV swift Ni8+ ions with fluences in the range 1 à 10 11-5 à 1013 ions/cm2 have been studied at RT. A broad and strong PL emission band with peak at â¼537 nm besides a sharp emission band with peak at â¼705 nm have been recorded in combustion synthesized mullite. However, a single broad emission with peak at â¼537 nm have been recorded in mullite synthesized by sol-gel technique at an excitation of 442 nm laser beam. It is found that PL intensity is decreases with increase of Ni8+ ion fluence. The decrease in PL intensity is attributed to destruction of Al-O and Si-O bonds in the samples. Infrared absorption (IR) studies of as it is and Ni8+ ion irradiated mullites have also been studied and results obtained are discussed. © 2003 Elsevier B.V. All rights reserved

Wide-angle α-t coincidence measurement in the breakup of 7Li on 27Al

We have performed wide-angle in-plane coincidence measurements of the alpha particles and tritons emitted in the 48-MeV 7Li projectile breakup reaction on 27Al. The data have been analyzed using the post-form distorted-wave Born-approximation (DWBA) theory of breakup reactions where Coulomb and nuclear breakup as well as their interference terms are included. The theory is able to provide a good description of the experimental data particularly at large relative angles between the fragments. The interference between the Coulomb and nuclear breakup modes is found to be significant

Study of α-transfer reaction 28Si( 7Li, t) 32S

The 28Si( 7Li, t) 32S reaction has been studied at 48 MeV. Using a αt potential overlap based on a microscopic cluster model, the full finite-range distorted wave Born approximation analysis was carried out for nine low-lying states; 0.0 MeV (0+), 2.23 MeV (2+), 3.78 MeV (0+), 4.46 MeV (4+), 5.01 MeV (3-), 5.80 MeV (1-), 6.76 MeV (3-), 7.43 MeV (1-) and 8.49 MeV (1-) of the residual nucleus. A re-analysis was also done for the same states of 32S having an αd overlap for the reaction 28Si (6Li, d) 32S at 75.6 MeV. Theoretical spectroscopic factors have been calculated for the measured even-parity states of 32S using the shell model code OXBASH. The spectroscopic factors were compared for both the reactions

Inclusive and exclusive measurements in the projectile breakup of 7Li

The inclusive and exclusive measurements were carried out for 7Li projectile breakup on 27Al target at 48 MeV. In the inclusive data we have observed a broad peak around the beam velocity for alphas and tritons. The exclusive data for alpha-triton coincidences show good agreement with the post-form DWBA theory of breakup reactions

Coupled channel description of 16O+142,144,146Nd scattering around the Coulomb barrier using a complex microscopic potential

Angular distributions of elastic scattering and inelastic scattering from 2+ 1 state are measured for 16O+142,144,146Nd systems at several energies in the vicinity of the Coulomb barrier. The angular distributions are systematically analyzed in coupled channel framework. Renormalized double folded real optical and coupling potentials with DDM3Y interaction have been used in the calculation. Relevant nuclear densities needed to generate the potentials are derived from shell model wavefunctions. A truncated shell model calculation has been performed and the calculated energy levels are compared with the experimental ones. To simulate the absorption, a 'hybrid' approach is adopted. The contribution to the imaginary potential of couplings to the inelastic channels, other than the 2+ 1 target excitation channel, is calculated in the Feshbach formalism. This calculated imaginary potential along with a short ranged volume Woods-Saxon potential to simulate the absorption in fusion channel reproduces the angular distributions for 16O+146Nd quite well. But for 16O+142,144Nd systems additional surface absorption is found to be necessary to fit the angular distribution data. The variations of this additional absorption term with incident energy and the mass of the target are explored. © 2003 Elsevier Science B.V. All rights reserved

A microscopic complex potential description of elastic, inelastic cross section in the Coulomb nuclear interference region in the 28Si on 28Si system

Elastic and inelastic angular distribution and excitation functions were measured for the 28Si + 28Si system in the vicinity of the Coulomb barrier. While the elastic data could be described very well by using fully microscopic complex potential, the inelastic cross sections were found to be more sensitive to small variations in the potential. In particular the Coulomb nuclear interference dip observed in the inelastic excitation functions could not be fitted satisfactorily with calculation. Inclusion of an energy dependent term of Gaussian shape to the associated matrix element with the reorientation coupling in the phenomenological calculations leads to a better fit the inelastic excitation functions. © 1998 Elsevier Science B.V

Microstructural and plasmonic modifications in Ag-TiO₂ and Au-TiO₂ nanocomposites through ion beam irradiation

The development of new fabrication techniques of plasmonic nanocomposites with specific properties is an ongoing issue in the plasmonic and nanophotonics community. In this paper we report detailed investigations on the modifications of the microstructural and plasmonic properties of metal–titania nanocomposite films induced by swift heavy ions. Au–TiO2 and Ag–TiO2 nanocomposite thin films with varying metal volume fractions were deposited by co-sputtering and were subsequently irradiated by 100 MeV Ag8+ ions at various ion fluences. The morphology of these nanocomposite thin films before and after ion beam irradiation has been investigated in detail by transmission electron microscopy studies, which showed interesting changes in the titania matrix. Additionally, interesting modifications in the plasmonic absorption behavior for both Au–TiO2 and Ag–TiO2 nanocomposites were observed, which have been discussed in terms of ion beam induced growth of nanoparticles and structural modifications in the titania matrix