[en] Hydrogen plays a crucial role in the properties of various materials, devices and in growth of hydrogenated amorphous materials. Therefore, its quantification and determination of concentration at various depths is of immense interest. Among various techniques of hydrogen depth profiling, the nuclear techniques being non-destructive in nature are widely used. Elastic recoil detection analysis (ERDA) with helium ions was first used for hydrogen depth profiling. Later on, the heavy ions were utilised due to certain advantages. It has been shown recently by us that H along with other elements in thin film up to Ca can be detected simultaneously with heavy ion ERDA, if the elements being detected are well separated in masses. It also has been shown that even the neighbouring elements such as C,N,O along with H can be detected provided a ΔE-E detector telescope is used in ERDA. The time of flight (TOF) with ERDA, nuclear reaction analysis (NRA), neutron TOF are other nuclear techniques for hydrogen profiling. There are, however, certain problems that arise in nuclear techniques such as hydrogen loss during the measurement, which must be taken into account for accurate and reliable results. A scenario of developments in nuclear techniques with suitable examples is given. (author). 26 refs., 9 figs., 1 tab

[en] Swift heavy ions (SHI) available with 15 MV Pelletron accelerator at NSC Delhi are utilized for modification and characterization of materials. Problems related to electronic sputtering, interface modifications, ion beam induced epitaxial crystallization, phase transitions and nano phase generation by SHI's are of current interest. The experimental results in the field of ion beam mixing and electronic sputtering are explainable in framework of thermal spike model. An overview of the current research activities in materials science with swift heavy ions is given. (author)

[en] Irradiation of materials, by high energy, heavy ions (referred to as swift heavy ions or SHI), results in highly excited lattice atoms with negligible contribution from elastic collisions. Atomic displacements and structural modifications of such a lattice, brings out interesting changes in the materials. Silicide formation at the interface in Ti/Si and Fe/Si has been observed due to electronic excitation-induced ion beam mixing. SHI irradiation of organic crystals shows significant changes in dielectric constant providing a possibility of making buried optical waveguide structures. The irradiated polymers after etching give micro-filters, which can be used in different ways. Ion track diameters have been estimated from the monitoring of hydrogen release, using elastic recoil detection, during ion irradiation of polymers. Possibilities of having an insight to varying damage zones inside a track are demonstrated. (author)

[en] Ion beams play a vital role in materials in different ways. Ions of energies from eV to hundreds of MeV have been useful in different ways, e.g. the growth of thin films, modification of materials and the analysis of materials. Tens of keV to hundreds of keV ion beams are used for doping diamond, DLC and fullerene films. As damage results in this process, the radiation damage studies are of importance. Elastic recoil detection analysis (ERDA) using heavy ions is utilised for hydrogen and carbon depth profiling in DLC and diamond films. The analysis of DLC and diamond films by ion beam techniques provides a better understanding of the growth of these films. Other properties -adhesion, hardness resistivity, refractive index, etc. - can be correlated to the hydrogen content of the films, which is present from their growth process. High energy heavy ions are used for materials modification by inelastic collision process which results in either electronic excitation or ionisation of the atoms; it also causes breakage of C to H bonds with H loss in the film. The modifications produced by energetic ions have been desirable as well as undesirable. In the application of ion beams the promising area is the doping of diamond film for devices and doping of fullerene films with K for superconducting properties. (author)

[en] Thermoluminescence (TL) of natural kyanite single crystals bombarded with 100 MeV Si⁺⁸ ions with fluences in the range 1x10¹¹-5x10¹³ ions/cm² has been studied at room temperature (RT). Two TL glows, a medium one at ∼445 K and another intense one at ∼550 K are recorded in single crystals of kyanite. However, in the case of pelletized samples, similar TL glows but with peaks at ∼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

[en] The concentration and depth profile of an element in host material decides its properties and therefore it is of immense interest to material scientists. Out of many techniques which are employed for surface and depth analysis, the accelerator based nuclear techniques have a unique feature of probing the material under investigation in a non-destructive way. (author). 9 refs., 8 figs

[en] In heavy ion reactions, the singles spectra are quite complicated due to the existence of many exit channels. Identification and quantification of isotopic composition in outgoing channels is required for understanding of reaction mechanism. ΔE-E telescope provides a tool to separate particles of different Z and therefore energy spectra of different outgoing particles can be extracted. However the telescope is not suitable to separate out different isotopes of the species above Z = 5. Time of flight (TOF) with the telescope enables one to identify both Z and M. TOF technique and pulse shape analysis are useful in n-γ discrimination for neutron detection also. TOF can be carried out with pulsed ion beam or DC beam. Various aspects of particle identification with telescope along with TOF technique, kinematic coincidence and n-γ discrimination are discussed with suitable examples. (author). 33 refs., 5 figs

[en] The free volume modifications in carbon-ion irradiated poly (ethylene terephthalate) (PET) have been investigated using positron lifetime method and sorption kinetics by the gravimetric method. The positron results indicate the formation of linear tracks and free radicals. Iodine sorption suggests Longmuir type of filling of the free volume sites by iodine in the initial stages of sorption, and in the later stages, swelling and conformational changes dominate. Using dual sorption model, diffusion- and relaxation-controlled sorption have been separated. Further, it has been found that the diffusion process deviates from Fick's law and hence from Fujita's free volume theory for both virgin and C-ion irradiated PET

[en] Full text: Energetic ions, depending on their mass and energy, play crucial role in synthesis and engineering of the nanostructures. Broadly, the areas of research and investigations of ion beams in nanostructuring are (i) synthesis of nanostructures and (ii) study of the modifications of existing buried nanoparticles in a matrix so as to explore the possibility of engineering the size and shape of the nanostructures. Inter University Accelerator Centre (IUAC) has the facilities to provide (i) 1-1.5 keV wide beam (2 inch diameter) (ii) typically ∼100 keV to I MeV ions and (iii) swift heavy ions (energies from 50 MeV to 200 MeV). I will brief some results on the synthesis of noble metal nanoparticles embedded in silica, ZnO and polymer matrix, along with some preliminary experiments on possible applications. The unique feature of the swift heavy ions, of crating ion tracks in insulators of dimension from a few nm to about 10 nm, is used to engineer the size and shape of the particles embedded in silica matrix. On the basis of several experiments at IUAC, it is shown that the embedded particles either grow in size or reduce in size, if they are smaller then the ion track size. The shape transformation from spherical to elongated along the beam direction occurs, when the particle size is larger than the ion track in silica. The tuning of the surface plasmon resonance in noble metal particles embedded in insulating, transparent matrix will be briefed. The unique feature of SRI is also used in creation of conducting C nanorods in fullerene matrix by irradiation of thin fullerene film by 100 MeV Au ions. Clusters of C aligned in nano dimension ion tracks are formed by swift heavy ion irradiation of Si based gels

[en] Short communication. 3 refs., 2 figs