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The polymer blends of Polymethyl Methacrylate/Polystyrene (PS/PMMA) have been irradiated with 28 Si ions of 60 MeV. The percentage transmission of light in the wavelength region of 490 nm has been studied with varying concentration of PS in blend films before and after irradiation. The transmission of light increased on irradiation which may be attributed to the chain scissions of PMMA.
Swift heavy ions (SHI), ions with energy which produce large electronic energy loss are now being used for modification of the properties of the materials through electron phonon coupling. Characteristic defects produced by heavy ions in insulators can also be produced in other materials if sufficient energy can be locked into electronic energy which can be transferred to the lattice. Electronic energy...
Heavy ions with energies of a few tens of MeV and higher available at NSC Pelletron have applications in materials characterization and modifications. Nuclear techniques have been exploited for materials analysis by elastic recoil detection analysis (ERDA). High energy heavy ions and gaseous ionization chamber based telescope detector or Bragg curve spectrometer adds to the strength of ERD technique...
The electret state of a polymer arises from the induced polarization owing to the frozen in phenomenon of electric charges. The study of electret nature using thermally stimulated discharge current (TSDC) technique reveals the nature of various relaxation processes in a polymer. When a polymer is irradiated with high energy ions their dielectric relaxations get affected which can be investigated using...
Interaction of swift heavy ion beam with copper oxide based high temperature superconducting (HTS) materials is discussed. The thin films and crystals of HTS are irradiated by swift heavy ion beam in a vacuum chamber to produce the columnar defects as per our requirements. These controlled columnar defects serve as pinning centers for vortices. This phenomenon is of interest in increasing critical...
The present work reports the results of in-situ resistivity measurement in thick films of YBCO while they were irradiated by Ag, Ni and O ions in the MeV range obtained from the pelletron at NSC, New Delhi. The resistance measurement was done in-situ in seconds interval to probe into the system evolution during irradiation and after the beam is switched off. The irradiated samples were thin enough...
The effects of 100 MeV Oxygen and 200 MeV Silver ions on the structural and transport properties of YBCO thin films are reported. Both normal state and superconducting properties were studied on Laser ablated and high pressure oxygen sputtered films. Precise electrical resistance and critical current measurements near T c were made and the data obtained were analysed in the light of existing...
MeV energy ion-implantation induced modifications in simple binary glass As 2 Se 3 have been monitored by de conductivity measurements. The study testifies that the process of ion-implantation at MeV energy is a novel technique in modifying the electronic properties of semiconductors. Ni ion seems to have more drastic changes than Ag and Ge ions. As small a dose of 75 MeV Ni ions as...
The technique of elastic recoil detection analysis was used to study hydrogen absorption by a non-evaporable getter (NEG) material st 707, an alloy of Zr, V and Fe. The depth distribution and intake of hydrogen in the samples activated at different heating temperatures showed that the hydrogen intake was optimum at about 300°C and tended to fall at higher temperatures from desorption. The maximum...
Infra-red transmission and electrical characteristics of single crystal GaAs substrates implanted with 70 MeV 120 Sn ions have been in vestigated after implantation and subsequent annealing treatments. The optical density αx is found to increase with implanted dose over photon energy range 0.6-1.4 eV and reaches a high saturated value for the samples implanted to a dose of 1 10...
Two new organic nonlinear single crystals viz., Methyl hydroxy benzoate (MHB) and p-hydroxy Acetophenone (HAP) are irradiated with swift heavy ions Ag 100 MeV and Si 50-100 MeV, from the 15 UD pelletron at NSC Delhi. Hydrogen depth profiling was carried out by using ERDA technique. The effect of irradiation on the dielectric, nonlinear optical properties have been investigated. A dramatic increase...
Diamond films are synthesized using hot filament chemical vapour deposition (HF-CVD) method. The films are irradiated by high energy boron ions using Pelletron accelerator, followed by thermal annealing treatment to achieve doping. It is shown that this method of doping avoids surface disorder and graphitization in the films, which in turn facilitate viable scanning tunneling microscopic (STM) investigations...
The total secondary electron yields Y were measured for 100 MeV Si 7+ ions on Be, Al, Si, Ni, Ag and Au as a function of the incident angle of projectile ranging from 0° to 65°. In order to compare the angular dependence of the electron yield for Si 7+ ions using different targets, the experimental curves were fitted by the empirical relation of the form Y(θ) = Y(0)(cosθ)...
Pd/p-Si and Pd/n-Si devices were irradiated from 100 MeV gold (7+) ions for varying doses (∼ 10 11 -10 13 ions cm -2 ). The devices were characterized from I-V and C-V studies. It has been found that there is a change of conductivity type i.e. from n to p at a probed depth of ∼ 8 μm which is approximately the stopping range of the gold ions in silicon. A deep...
Surface modification and characterization are being undertaken increasingly using the MeV heavy ion beams. Interpretation of such data requires reliable and precise values of stopping powers involved. Sufficient data exists above 2.5 MeV/n but less information is available at lower energies. The present series of experiments report the results of stopping power measurements for various ion species...
This paper reports the effects of MeV ion irradiation on the adhesion and quality of diamond films on WC-Co tool-bits and silver films on soda glass. Diamond films of about 3 μm thickness were prepared, using the hot filament CVD technique, on WC-Co tool-bits. Silver films of 1000 thickness were prepared, using the Joule evaporation technique, on soda glass. 100 MeV 127 I beam...
In recent years, a number of groups around the world have optimised and used heavy ion elastic recoil detection analysis (HIERDA) to study materials science problems, which are intractable with other techniques, but HIERDA remains a technique with many unresolved issues. There is no standard methodology for analysing HIERDA spectra and extracting accurate depth profiling information. While 'slab'...
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