Department Of Physics
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Item Role of energy loss-range profile of heavy ions in tailoring the optical properties of polycarbonate(Elsevier B.V., 2021-09-27T00:00:00) Chhokkar, Preeti; Kumar, V.; Goyal, Parveen K.; Kumar, Shyam; Tomar, A.K.; Gaur, Anurag; Arya, AnilPolycarbonate (PC) samples have been implanted with 115 keV N+, Ar+ and Kr+ at fluences ranging from 5x1014 to 1x1016 ions/cm2 to be employed for optical studies. A Decrease in optical energy gap, enhancement in reflectivity and reduction in transmittance, particularly in UV-region, is observed for all implanted samples. The change in optical properties of PC, first, by keeping energy deposited/cm2 constant (i.e. keeping energy*fluence constant) and then by keeping same depth of penetration for different ions have been analysed in detail. The changes are found to be more prominent for N+ compared to Ar+ and Kr+ when the fluence/energy deposited/cm2 by the ions is same. Further, the energy for N+ is reduced to 46 keV, while for Kr+ it is increased to 200 keV to ensure the same penetration depth for N+, Ar+ and Kr+ in PC. Finally, the results are explained on the basis of energy loss-range profiles of these ions in polycarbonate and through Raman spectroscopy. This study convincingly demonstrates that not only the types of ion species, their energies and fluences, but the total energy deposited by ions and their depth of penetration also plays an important role in tailoring the optical properties of polymeric materials. � 2021 Elsevier B.V.Item Design and development of a compact ion implanter and plasma diagnosis facility based on a 2.45 GHz microwave ion source(American Institute of Physics Inc., 2021-05-25T00:00:00) Swaroop, Ram; Kumar, Narender; Rodrigues, G.; Kanjilal, D.; Banerjee, I.; Mahapatra, S.K.A project on developing a 2.45 GHz microwave ion source based compact ion implanter and plasma diagnostic facility has been taken up by the Central University of Punjab, Bathinda. It consists of a double-wall ECR plasma cavity, a four-step ridge waveguide, an extraction system, and an experimental beam chamber. The mechanical design has been carried out in such a way that both types of experiments, plasma diagnosis and ion implantation, can be easily accommodated simultaneously and separately. To optimize microwave coupling to the ECR plasma cavity, a four-step ridge waveguide is designed. Microwave coupling simulation for the ECR plasma cavity has been performed at different power inputs using COMSOL Multiphysics. An enhanced electric field profile has been obtained at the center of the ECR plasma cavity with the help of a four-step ridge waveguide compared to the WR284 waveguide. The magnetic field distribution for two magnetic rings and the extraction system's focusing properties have been simulated using the computer simulation technique. A tunable axial magnetic field profile has been obtained with a two permanent magnetic ring arrangement. The dependency of the beam emittance and beam current on accelerating voltages up to 50 kV has been simulated with different ions. It shows that ion masses have a great impact on the beam emittance and output current. This facility has provision for in situ plasma diagnosis using a Langmuir probe and optical emission spectroscopy setups. This system will be used for ion implantation, surface patterning, and studies of basic plasma sciences. � 2021 Author(s).