[en] The ongoing radiation biology research at IUAC investigates the effects of accelerated charged particles on the biological systems at the molecular level. There is a dedicated beamline for Heavy Ion Radiation Biology for experiments using the low flux of accelerated ions. The areas of research include modeling of radiation effects, exploration of pathways to radiation induced effects with potential applications in many important areas such as Heavy Ion Cancer therapy and Radiation protection in manned space flights. IUAC has a dedicated radiation biology beamline having ASPIRE (Automated Sample Positioning and Irradiation system for radiation biology Experiments) where cells can be irradiated in air at atmospheric pressure to the preset dose of accelerated heavy ions with a very good dose uniformity. Apart from that, there is a dedicated radiation biology laboratory having basic equipment to facilitate the sample preparation and post irradiation treatments like CO₂ incubators, Image based cell counter, an upright Fluorescence microscope, Multimode Plate Reader, Field Inversion Gel electrophoresis two bio safety cabinets, one small laminar flow bench, refrigerated centrifuges, a microplate washer and deep refrigerators. The facilities allow for conducting analytical procedures involving gene expression studies using PCR, Western Blot, Fluorescence Immunostaining studies etc. by the university users. The talk will discuss some of the studies undertaken utilizing IUAC facilities. Signaling pathways of activation and secretion of Matrix Metalloproteinases from human lung carcinoma cells and Radiosensitization of human cancer cells using G-quadruplex ligands have been studied. Recently, the group has intensively studied the effects of 62 MeV carbon ion beam on mitochondrial fission-fusion homeostasis and electron transport chain (ETC) function in HEK 293T cells. In another study, modulation of autophagy and the related mechanism by 62 MeV C ion beam in human embryonic intestinal cells (INT407 cells) were investigated without and with treatment with autophagy inducers/blockers. There is an indication that LiCl treatment can be used as a radio-protective agent against autophagy. Conversely, pre-treatment with autophagy inducers increased the accumulation of monodansylcadaverine and altered the distribution and size of the autophagic vacuoles in ion irradiated cells. (author)

[en] An electron cyclotron resonance (ECR) based medium energy ion beam facility, known as High Fluence Ion Beam Facility (HFIBF), is commissioned at Nanotechnology Application Centre, University of Allahabad. The facility is a user facility for ion beam driven materials synthesis, properties modification and their characterizations. The source can be operated up to maximum of 25 kV extraction and 300 kV platform potential and it includes RF plasma, oven and sputter ion sources for gases, low melting point metals and high melting points metal ions generations, respectively. The main advantages of the facility is the high flux and large area scanning. (author)

[en] The electronic sputtering of LiF thin films due to 120 MeV Ag^9- irradiation has been studied. The sputtering yield of these films of different thicknesses deposited on different substrates is determined by elastic recoil detection analysis. We have studied the effect of the thickness of the film on the electronic sputtering process. The results show that the sputtering yield is of the order of 10³ atoms/ion and the sputtering decreases with increasing thickness of the film. On the other hand, the film deposited on insulator substrate shows higher sputtering. These aspects are discussed in the framework of thermal spike model. (author)

[en] Present work deals with the comparative study of micro-structural and electrical properties of conventionally and microwave (MW) heat treated dysprosia stabilized zirconia electrolyte for solid oxide fuel cell application. Characterizations have been evaluated by means of X-ray diffraction (XRD) and scanning (SEM), and complex impedance analysis respectively. The amount of dysprosia was varied from 2 to 10 mol% in zirconia. The addition of dysprosia (8-10 mol % in conventionally sintered DySZ and 4-10 mol% in MW sintered DySZ) stabilized the cubic zirconia phase, which was analyzed from XRD analysis. SEM micrographs clearly showed the grain size but high density in MW sintered DySZ compare to conventionally sintered DySZ compounds. Complex impedance analysis was performed in the temperature range from 250 to 600℃. The results indicated a dominant contribution comes from grain boundary resistance by both ways heat treated DySZ samples. D.C. conductivity increases with dysprosia doping up to 6 mol% (conventional sintered) and 8 mol% (for MW sintered) and thereafter showing a reverse trend. Magnitude of DC conductivity found to be higher in MW sintered DySZ than conventional DySZ. (author)

[en] The angular distribution of the sputtering yield from highly oriented pyrolytic graphite sample irradiated with a 130 MeV Ag beam is studied. The beam was incident perpendicular to the sample and the sputtered carbon was collected on Si catcher foils which were studied using a high resolution ERDA set up. An anisotropic distribution of sputtering is observed with a distribution C=Acos^1.3Θ+Bexp(-(Θ-53)²/σ²) which shows that a peak lies at around 53 deg. on a distribution which otherwise is a over-cosine function. The maximum sputtering yield is observed at 53 deg., falling rapidly to almost zero at 90 deg., with an average sputter yield of 5.5 x 10⁵ atoms/ion. It is suggested that this anisotropy may be due to the crystal structure and formation of a pressure pulse

[en] Swift heavy ions induced effects on optical (color centers), structural and surface (electronic sputtering and morphology) modifications, in nano-grains LiF thin films were studied by glancing angle X-ray diffraction, optical absorption, photoluminescence and elastic recoil detection analysis techniques. Our results show that grain size and irradiation temperature play a crucial role in materials modifications as a function of fluence for the selected ion beam parameters. Also for the first time, lamellae formation was observed in LiF thin films after a high fluence irradiation of 5 x 10¹³ ions/cm² at liquid nitrogen temperature with 120 MeV Ag ions irradiation under grazing incidence (∝10 ). (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

[en] Photoluminescence (PL) properties of swift heavy ions-induced F₂ and F₃⁺ color centers in nano-granular lithium fluoride (LiF) thin film were studied. LiF films were deposited on glass and silica substrates and irradiated with various ion species (Ag, Ni and Au) at different irradiation temperatures. The role of ion species, their fluence and the irradiation temperature on the PL intensity of color centers induced in LiF thin films is discussed

[en] In the present work, (Fe/Cr/Al)x10 multilayer having different thicknesses were deposited using electron beam evaporation in an UHV chamber and were irradiated with 120 MeV Ag⁹⁺ ions to observe change in structural and magnetic properties at interface. X-ray reflectivity measurement shows that the height of Bragg peak deceases fast for lower thickness than the higher thickness. The diffusion length L2 d as a function of ion fluence indicates that the mixing is higher for lower multilayer thickness as compare to higher. Magneto-optic Kerr effect (MOKE) shows Fe/ Cr/Al multilayers are soft in nature and have different in-plane anisotropy in as-deposited multilayers. As a function of fluence, coercivity trend has been observed opposite for different thickness of Fe/Cr/Al multilayer due to different interface mixing. Fe and Cr K-edges x-ray absorption fine structure (XAFS) were used to determine local Fe-Fe and Fe-Cr coordination number, distortion in bond distance and Debye-Waller (DW) factor as a function of multilayer thickness and mixing due to ion beam irradiation. The multilayer thickness dependence mixing can be understood in terms of the thermal spike model by taking into consideration the changes in the electron mobility due to scattering from surface and interfaces

[en] The topographic and spectroscopic (I-V) characteristics of the defect structures created by SHI irradiation of HOPG and ⁶⁰C using an ambient scanning tunneling microscope (STM) and an atomic force microscope (AFM), have been studied. Various types of defect structures on the surface of highly oriented pyrolytic graphite (HOPG) are observed. The results of spectroscopic studies of pristine and 110 MeV Ni ion irradiated C₆₀ surface are also studied and the differential conductivity (dI/dV) as function of bias using lock-in amplifier of the irradiated sample shows a reduction in flat region implying a reduction in the band gap after irradiation besides an increase in the linearity of the non-linear characteristics. (author)

[en] Thermally grown thin films of LiF were irradiated with 150 MeV Ag ions at various fluences. The quality of films was studied using GAXRD, which shows that films are c-axis oriented. It also shows that grain size decreases and the intensity of (200) orientation enhances with fluence, which is the preferential orientation. These results are further confirmed by photoluminescence studies, which shows that the concentration of F₃⁺ and F₂ color centers decreases with ion fluence due to increase in surface to volume ratio under Swift Heavy Ion (SHI) irradiation. (author)