009798   Vishwakarma S R;Verma A K;Tripathi R S N;Das S;Rahul (Physics & Electronics Dep, Dr R M L Avadh University, Faizabad-224 001, Email: srvfzb@rediffmail.com) : Structural property of n-type indium antimonide thin films. Indian J pure appl Phys 2012, 50(5), 339-46.

In present study, the n-type indium antimonide (InSb) thin films of thickness 300 nm were deposited on glass substrate at room temperature under the high vacuum ~10^-5 torr using starting materials. The starting materials have been prepared under vacuum ~10^-5 torr in vacuum coating unit using indium (99.999%) and antimony (99.999%) metal powder as source materials with various non-stoichiometric composition as In_1-xSb_x (0.2 <60> x <60> 0.4). The Energy Dispersive Analysis of X-rays (EDAX) measurement provides the information of chemical composition (In/Sb) in thin films. X-ray diffraction studies of starting materials and thin films confirmed the formation of InSb with polycrystallinity and orientation of crystallites along the (111) and (220) planes. The surface morphological study of thin films by scanning electron microscope reveals the crystalline nature which was found to be in good agreement with the XRD crystallinity analysis. The particle size (D), dislocation density (δ) and strain (ε) have been evaluated using XRD data for the starting materials and thin films. It is observed from X-ray diffraction patterns and scanning electron micrographs that particle size, dislocation density and strain are changing with composition ratio (In/Sb) in starting materials and their thin films.

21 illus, 3 tables, 15 ref

009797   Vishal Kumar;Tyagi S;Singh K (School of Physics and Materials Science, Thapar University, Patiala-147 004, Email: kusingh@thapar.edu) : Optical and invitro bioactive properties of sodium silicate glasses. Indian J pure appl Phys 2012, 50(5), 335-8.

Sodium silicate based glasses have been synthesized by melt quenching technique. The surface reactivity of resultant glasses has been analyzed by immersion studies in simulated body fluid solution (SBF) for different time duration. The formation of hydroxyapatite layer has been studied through weight change (loss/ gain) of glass sample and change in pH of SBF solution. The addition of Al₂O₃ instead of P₂O₅ in sodium silicate glasses increases the durability of glasses in SBF solution. The optical band gap decreases with increase of sodium oxide content with soaking time of glass in SBF.

5 illus, 2 tables, 23 ref

009796   Vasudevan P;Thomas S;Karthika S;Biju P R; Joseph C;Unnikrishnan N V (School of Pure & Applied Physics, Mahatma Gandhi University, Kottayam-686 560, Email: nvu100@yahoo.com) : Fluorescence enhancement in Sm<. J Optics 2011, 40(3), 96-100.

The hybrid matric contaning TiO₂ nanocrystals and Sm³⁺ ions prepared by the non hydrolytic sol-gel method, displaysthe characteristic emission of Sm³⁺ ions at the excitation energy corresponding to the energy gap of the TiO₂ namocrystals. On the other hand, emission of Sm³⁺ was too weak to be observed for the sample containing Sm³⁺ ions alone. The structural and optical analyses of the samples were carried out using X-ray diffraction technique, transmission election microscopy, Raman spectroscopy and emission spectroscopy. The TEM image of the sample shows that the TiO₂ nanocrystals are well dispersed in the PVP matrix and the XRD confirms the anatase phase of the TIO₂ nanocrystals. The enhancement of the emission is attributed to the energy transfer from the TiO₂ nanocrystals to Sm³⁺ ions.

5 illus, 19 ref

009795   Uniyal M;Bhatt S C (Physics Dep, H N B Garhwal University, Srinagar Garhwal-246 174, Email: mani_uniyal@hotmail.com) : Temperature dependence of width and soft mode frequency in sodium potassium tantalate mixed system. Indian J pure appl Phys 2012, 50(4), 248-51.

Considering a quadratic anharmonic model Hamiltonian and using Green's function and Dyson's equation technique, expressions for the width in the frequency response for mixed perovskite type ferroelectrics and soft mode frequency have been obtained. Using the experimentally observed dielectric constant and loss tangent for Na_1-xK_xTaO₃ (where x = 0, 0.2, 0.4, 0.5 and 0.6) the temperature dependence of soft mode width and frequency in these samples at 10 kHz has been calculated.

2 illus, 2 table, 21 ref

009794   Udupa D U;Shukla R P;Mantravadi M V (Applied Spectroscopy Div, Bhabha Atomic Research Centre, Mumbai-400 085, Email: dudupa@barc.gov.in) : Critical angle refractometer for heavy water anlaysis. J Optics 2011, 40(3), 107-13.

Indigenous design and fabrication of a critical angle refractometer is presented for measuring the percentage purity of heavy water. The paper describes the optical design of a critical angle prism used in the instrument for obtaining achromatism. Based on the suitable optical design, a fused silica glass prism has been fabricated and used for constructing a critical angle refractometer suitable for heavy water analysis. The instrument has been calibrated for measuring the percentage purity of heavy water with light water as an impurity in the purity range of 0%-100%. The accuracy of measurement is found to be ±4%. The refractometer is useful for quick estimation of heavy water from samples collected in different containers due to possible leakage of heavy water in reactor pipelines.

4 illus, 3 tables, 22 ref

009793   Thelin B (NO, , Solarphotonics HB, Granitvagen 12B Uppsala, Sweden, Email: btn602003@yahoo.se) : New intensity formula for ionic spectra. Indian J pure appl Phys 2012, 50(4), 231-6.

The new intensity formula in optical emission spectroscopy for the use of ions has been developed. The formula is built up on four different parts: The C-factor, wavelength dependence term, ionization energy term and the Planck factor. The method used in this very paper is the absolute intensity method which is described in many papers in the past. The experimental data are coming from NBS-tables of spectral intensity data from arc measurements of different elements. Nice linear relationships are obtained for oxygen ions in energy ranges of about 25-200 eV up to the 6^th ionization stage and energy ranges of about 30-160 eV for neon ions up to the 6^th ionization stages. A general formula for ions is presented including a sum of ionization energies from different ionization stages in the ionization energy term. The electron temperature has also been determined for atoms and ions of many elements. These electron temperatures are found to be in agreement with the energy distribution of secondary electrons from many experimental results from the literature.

12 illus, 4 tables, 12 ref

009792   Tahir M;Bhattacharya K;Chakraborty A K (Jhikra High School, , Jhikra, Joypur, Howrah-711 401, Email: kbaphy@caluniv.ac.in) : Modification of diffraction pattern of a slit using polarized light having variable state of polarization. J Optics 2011, 40(3), 101-6.

In has been established that the polarization properties of light can be effectively utilized in modifying the characteristic of the imaging system. As a matter of fact, the diffraction properties of the lens get modified when it is masked by polarizing devices. It is therefore well expected that characteristics of an imaging system also be modified by utilizing polarization properties of light. This calls for a systematic study of the effects of variation of polarization on diffraction pattern of different kinds opf slit including polarizaing devices. In this paper we study the Fraunhofer diffraction pattern of a slit using polarized ligh having variable state of polarization across it.

3 illus, 12 ref

009791   Sharma U D;Joshi V;Munish Kumar (Physics Dep, G B Pant University of Agriculture and Technology, Pantnagar-263 145, Email: munish_dixit@yahoo.com) : Equation of state and bulk modulus of C₆₀ solid. Indian J pure appl Phys 2012, 50(4), 245-7.

The soft core DY potential model for C₆₀ solid is critically examined in the light of theoretical and experimental studies. It is found that the soft core DY potential deviates largely as far as the theory and experiment are concerned. A simple model is, therefore, proposed to study the effect of pressure on C₆₀ solid. The model is applied to study the equation of state (EOS) and pressure dependence of bulk modulus in the light of other relations. A good agreement between theory and experiment supports the validity of the model proposed.

2 illus, 9 ref

009790   Sahu D K;Yadav V S;Gupta A K;Shankar Lal;Sahu S K (Physics Dep, R.S. Government Degree College, Lalitpur-284 243) : Steady state conduction current of doped polyaniline(PANI) film electrets state. Nano Vision 2011, 1(2), 54-63.

The variation of steady state conduction with applied electric field and temperature has been studies in solution-grown hydrochloric acid (HCL) doped Polyaniline (PANI) film 25μm. The study of the steady state conduction current variation with the polymer thickness and with its temperature shows that only the Poole-Frenkel effect can explain the experimental results .Also, hysteresis and polarisation effects were observed in the I-E characteristics. The slop value (m) in the lower field region lies between 1.2 to 1.5 and 1.97 to 2.00 at higher field strength. The activation energy is found to decrease from 0.73eV to 0.65 eV for doped poly aniline as the field increases from 6 to 18 kV /cm.

8 illus, 44 ref

009789   Sahu D K;Gupta A K;Yadav V S;Khare P K (Physics Dep, R.S. Government Degree College, Lalitpur-284 243) : Thermally stimulated depolarization currents in tri-ethyleneglycol doped poly (methyl acerylate) film electrets. Nano Vision 2011, 1(2), 74-87.

Thermally Stimulated Depolarization Currents in tri-ethyleneglycol -doped poly (methyl acrylate) (PMA) film (25μm thickness) was measured under various polarizing conditions. It was found two current maxima one at lower temperature (β-peak) and the other centred at higher temperature (α-peak). The magnitude of peak currents has been found to increase with increase in polarizing fields. The activation energy for the β-peaks is the same for field dependent TSDC thermograms. It is also amenable to special doping mechanisms so that the electronic properties can be modified through the variation of the number of electrons or protonic acid doping. In summation, PMA exhibits a high potential for several technological applications. So by looking the Importance of this polymer we are reporting here some modified polymer and its TSDC for various applications.

1 illus, 3 tables, 26 ref

009788   Raghuvesh Kumar;Munish Kumar (Physics Dep, G B Pant University of Agriculture and Technology, Pantnagar-263 145, Email: munish_dixit@yahoo.com) : Effect of size on cohesive energy, melting temperature and debye temperature of nanomaterials. Indian J pure appl Phys 2012, 50(5), 329-34.

A simple model has been used to study the size dependence of cohesive energy, melting temperature and Debye temperature. Authors have considered W, Ag, Al, Co and Au for the study of size dependence of cohesive energy and Al, Au, Ag, Zn, Bi for size dependence of melting temperature. The results obtained are compared with the available experimental data. A good agreement between theory and experiment encouraged the authors to extend the model to study the size dependence of Debye temperature. The results obtained for the size dependence of the Debye temperature are found to be in good agreement with the experimental data. This supports the validity of the model developed.

13 illus, 3 tables, 14 ref

009787   Perpetua O;Joseph U (Physics and Astronomy Dep, University of Nigeria, P.O. Box 3238, Nsukka, 410001, Enugu State, Nigeria, Email: peepyyy@yahoo.com) : IRI and GPS TEC variations over Ilorin, Nigeria. Res Rev : J Space Sci Technol 2012, 1(3), 1-11.

Diurnal and day-to-day variations of vertical total electron content (VTEC) over an equatorial region (Ilorin, Nigeria; geographic 8.50°N, 4.55°E; geomagnetic 10.60°N, 78.41°E) is presented using data from the IRI model and from the AFRL-SCINDA (Air Force Research Laboratory - Scintillation Network Decision Aid) GPS receiver installed at the Ilorin station. A comparison between VTEC data from the two sources is also presented since a major concern in the work is to use available GPS-TEC data for the year 2010 to evaluate the performance of the IRI model in TEC prediction over the region, and to therefore inform a proposed use of the IRI model in TEC modeling over the African region. The results show generally good comparisons between the IRI TEC predictions and the GPS TEC measurements, results from the comparisons on diurnal basis were, as expected, better than those on day-to-day basis. The work also indicates that the lower TEC thresholds of the IRI predictions for the days observed occurred at around 04:00 UT while for the GPS measurements they occurred at around 05:00 UT.

8 illus, 4 tables, 19 ref

009786   Pandey N;Srivastava R K;Prakash S G (Electronics & Communication Dep, University of Allahabad, Allahabad-211 002, Email: rkumarsau@gmail.com) : Photoelectret effect in dysprosium doped zinc oxide. Indian J pure appl Phys 2012, 50(4), 260-4.

Photoelectret properties of ZnO and dysprosium doped ZnO have been studied. Dysprosium (Dy) has been mixed in ZnO by weight with varying proportion. ZnO:Dy (0.50%) exhibits maximum photopolarization. The variation of photoelectret charge with applied voltage, photopolarization time, dark depolarization time, intensity of illumination and wavelength of illumination has been studied. XRD and SEM studies show that particle size of ZnO and ZnO:Dy (0.50%) is the order of few hundred nano meters.

8 illus, 14 ref

009785   Pandey B;Srivastava S;Tiwari S N;Singh J; Shukla S N (Physics & Electronics Dep, Dr R M L Avadh University, Faizabad-224 001, Email: sachida_shukla@yahoo.co.in) : Qualitative analysis of small-signal modifed Szikai pair amplifier. Indian J pure appl Phys 2012, 50(4), 272-6.

A small-signal modified Sziklai pair (complementary Darlington pair) amplifier is proposed with an additional biasing resistance in the circuit. The proposed amplifier produces significantly high voltage gain with narrow bandwidth. Poor response of conventional Darlington pair amplifiers at higher frequencies is found to be absent in the proposed amplifier circuit. Variations in voltage gain as a function of frequency and different biasing resistances, bandwidth and total harmonic distortion of the amplifier have also been studied. Proposed amplifier may be useful for various analog communication applications.

6 illus, 5 tables, 12 ref

009784   Pal I;Agarwal A;Sanghi S (Applied Physics Dep, Guru Jambheshwar University of Science and Technology, Hisar-125 001, Email: ip_gjust@yahoo.com) : Spectral analysis and structure of Cu<. Indian J pure appl Phys 2012, 50(4), 237-44.

New series of cadmium bismuth borate (CBBC) glasses have been developed by varying bismuth content in the chemical compositions of 20CdO.xBi₂O₃.(79.5-x)B₂O₃, where x = 15, 20, 25, 30 and 35 mol % Bi₂O₃, containing 0.5 mol% of Cu²⁺ ions. These glasses have been prepared by melt-quench technique (1150°C in air) for verifying there UV filtration performance. From the measurement of UV absorption spectra, both direct and indirect band gaps have been evaluated. Also different physical properties of the prepared glasses have also been studied. The refractive index of prepared glasses has been measured by using Brewster angle method. The amorphous nature of the glasses has been confirmed by X-ray diffraction. The spectroscopic properties of the glasses have been investigated using optical absorption spectra and fluorescence spectra. Optical transmission spectra of Cu²⁺ ions doped CBBC glasses have shown two peaks at 450 nm (²B_1g → ²E_g) and 645 nm (²B_1g → ²B_2g). Emission spectra of (0.5 mol %) Cu²⁺: CBBC have revealed two emission transitions at 412 and 523 nm of both Bi₂O₃ and CdO, these glasses are found to be good moisture-resistant optical systems.

10 illus, 4 tables, 49 ref

009783   Okeke F N;Okpala K C;Idakwoji J (Physical and Astronomy Dep, University of Nigeria, Nsukka, Nigeria, Email: kingsley.okpala@unn.edu.ng) : Contribution of E- and D-layer to weak geomagnetic storm events in South Africa. Res Rev : J Space Sci Technol 2012, 1(1), 11-24.

Data from five ionosonde in Southern Africa have been analyzed to better appreciate the contributions of the E- and D-layers of the ionosphere in this region to weak geomagnetic storms. This attempt to quantify the exact contributions of the D and E-layers to weak geomagnetic storms during period of relatively quiet Sun has never been done in this region before. The results suggest that the E-layers contribute more than the D-layers.

8 illus, 1 table, 23 ref

009782   Kuila P;Mukhopadhyay S (NO, V.S. Mahavidyalaya, Manikpara, Midnapore-721 513, Email: puspendu77@rediffmail.com) : Alternative approach to realize all-optical soliton based encoder. J Optics 2011, 40(3), 84-7.

Proposes an analytical method to conduct an all-optical soliton based encoding operation, which can be operated at a very long distance without any power loss. For this purpose, externally triggered (longitudinally) electro-optic-modulators (EOM) and non-linear optical fiber are used and all the modulators are set in phase modulation mode. Main advantage of this proposed technique is that the process is all optical soliton based. To transfer the system from conventional optical to a soliton based one, the amplitude and the frequency of the externally applied sinusoidal electric field applied to the modulators should be chosen properly.

2 illus, 1 table, 9 ref

009781   Kuhwaha K;Shukla P;Nandini D;Singh P; Ramrakhiani M (Post Graduate Studies and Research in Physics and Electronics Dep, Rani Durgavati Vishwavidhyalaya, Jabalpur) : Electroluminescence from CdSe/PV A nano composites. Nano Vision 2011, 1(2), 64-7.

The synthesis of polymer nanocomposites is an integral aspect of polymer nanotechnology. It has been shown that the optical properties of a material can be improved by inserting nanoparticles with its polymer matrix. CdSe/PVA Nanocomposites with various pH values have been prepared using chemical technique. The investigations of the prepared samples show that the smaller C2dSe nanocomposits prepared with higher pH give EL in low voltage range.

2 illus, 6 ref

009780   Joseph Jeremiah J;Jyrwa B M (Physics Dep, North Eastern Hill University, Shillong-793 022, Meghalaya, Email: bjywa90@hotmail.com) : Poschl Teller model for the total cross-section of neutron scattering from <. Indian J pure appl Phys 2012, 50(5), 289-94.

Neutron scattering cross-section of ²³²Th have been investigated using an attractive potential. On applying the modified P”schl-Teller model, the total cross-section of the n+²³²Th in the energy range 5-20 MeV has been calculated. It was compared with the available experimental data and evaluated data of JENDL-4.0, ENDF/B-VII.0 and CENDL-3.1 as well as with the theoretical value from TALYS-1.2 Nuclear Reaction Program, EMPIRE: 2.19 Nuclear Reaction Model Code and are found to be in reasonably good agreement. This supports the validity of the present calculation.

6 illus, 1 table, 21 ref

009779   Jaya Prakash B;Buddhudu S (Physics Dep, Sri Venkateswara University, Tirupati-517 502, Email: jpsvut@gmail.com) : Synthesis and analysis of LiNbO₃ ceramic powders by co-precipitation method. Indian J pure appl Phys 2012, 50(5), 320-4.

Reports on the preparation and analysis of LiNbO₃ (LN) ceramic powder by a conventional chemical co-precipitation method. An aqueous mixture of ammonium carbonate along with ammonium hydroxide has been used. Lithium niobate ceramic powders have been sintered at 600, 700, 800, 900 and 1000°C, respectively. Structural analysis of this material has been carried out upon the measurement of XRD, SEM, EDAX Raman and FTIR spectral profiles systematically. Thermal, magnetic, dielectric (ε' and ε") ac conductivity (σ_ac) studies have also been investigated. XRD features of LiNbO3 ceramic powder reveal a hexagonal crystal structure (at an optimized temperature of 800°C) based on JCPDS card No: 20-631 and an average crystallite size of this powder has been calculated using the Scherrer's formula. The morphology of the LiNbO₃ ceramic powder has been studied and the particles are in nano sizes from the HRSEM image. Thermal properties of the as synthesized chemicals mix of the sample have been investigated from the measurement of its TG-DTA features. The dielectric properties of the LiNbO₃ have been studied and also its ferromagnetic behaviour has been verified.

9 illus, 35 ref

009778   El-Taher A;Abbady G E (Physics Dep, Faculty of Science, Al-Azhar University, Egypt, Email: Atef_Eltaher@hotmail.com) : Natural radioactivity levels and associated radiation hazards in Nile river seddiments from Aswan to El-minia, upper Egypt. Indian J pure appl Phys 2012, 50(4), 224-30.

The natural radionuclides ²²⁶Ra, ²³²Th and ⁴⁰K contents in the Nile river sediments at various locations in Upper Egypt from Aswan to El-Minia have been investigated using gamma spectrometric analysis. Determination and measurement of radionuclide concentration are of great importance for assessment of external radiation dose received by man. The range and mean values of ²²⁶Ra, ²³²Th and ⁴⁰K activity concentrations are 13-42 (29), 10-67 (45) and 74-139 (123) Bq kg^-1, respectively. These results are found to be in agreement with those reported data for Egyptian soil as 17 (5-64), 18 (2-96) and 320 (29-650) Bq/kg dry weight (UNSCEAR, 2000). The mean radium equivalent (Raeq) and dose rates are 100.21±10.01 Bq kg^-1, 44.88±6.69 n Gy h^-1, respectively. The measured activity concentrations differ widely as their presence in the Nile river depends on the pertinent environmental situation such as the presence of dams, barrages and sediments type. The other factors controlling the distribution of the detected natural radioisotopes have been discussed.

1 illus, 4 tables, 45 ref

009777   Dowluru R K;Bhima P R (ECE Dep, Jawaharlal Nehru Technological University, Kakinada, Andhra Pradesh, Email: dowlururavi_Kumar@yahoo.com) : Influences of third-order dispersion on linear birefringent optical soliton transmission systems. J Optics 2011, 40(3), 132-42.

Presents the propagation of solitons in linear birefringent single-mode fibers under the influence of third-order dispersion. The behaviour of two partial pulses evolved due to polarization mode dispersion is investigated under the presence of third-order dispersion (TOD). The analytic solutions to coupled nonlinear Schrodinger equations (CNLSE) with TOD are derived using multiple scale perturbation expansion and the results are compared with the solutions obtined using split-step Fourier method to find the effects of TOD on soliton propagation. It is found that the resultant soliton propagation. It is fopund that the resultant soliton deviates from its initial position with third-order dispersion and this deviation is considerably small when the pulse propagates relatively far from the zero-dispersion wavelength. It is observed that the behaviour of two partial pulses and their subsequent properties depend not only on te fiber parameters, But also on the amplitude of the launched soliton pulse.

14 illus, 20 ref

009776   Deshpande M P;Chaki S H;Patel J G;Bhatt S V; Garg N;Sathe V (Physics Dep, Sardar Patel University, Vallabh Vidyanagar-388 120, Email: vishwadeshpande@yahoo.co.in) : CdS nanoparticles and nanocrystalline thin films synthesized by chemical bath deposition technique. J Nanosci Nanoengng Applic 0000, 1(3), 8-15.

Cadmium Sulfide (CdS) nanoparticles and nanocrystalline thin films were synthesized by chemical bath deposition technique at room temperature. The elemental composition of the as-grown CdS nanoparticles and nanocrystalline thin films were determined by energy dispersive analysis of X-rays (EDAX). Crystallite size and lattice parameter were determined from X-ray diffractogram whereas transmission electron microscopy (TEM) image gave particle size and the selected area electron diffraction ring pattern showed the polycrystalline nature of these samples. The UV-VIS-NIR spectra indicated blue shift relative to the bulk form of the material. The Raman spectrum revealed two peaks which correspond to the longitudinal optical phonon mode at frequency 295.25 cm^-1 and 600 cm^-1 for CdS nanoparticles and at frequency 304.31 cm^-1 and 550 cm^-1 for thin film indicating good agreement with earlier reported result. An extra peak centered at 207.81 cm^-1 and 406.16 cm^-1 for CdS nanoparticles and thin films respectively corresponds to the surface phonon mode. Thermogravimetric analysis (TGA) carried out on CdS nanopartiles revelaed that the nanoparticles are thermally stable between 50° C to 600°C they start decomposing.

13 illus, 3 tables, 26 ref

009775   Choudhury N;Singh F;Sarma B K (Physics Dep, Pub Kamrup College, Baihata Chariali-781 381, Email: cnavajyoti@yahoo.co) : Effect of 100 MeV Ni<. Indian J pure appl Phys 2012, 50(5), 325-8.

Nanocrystalline PbS prepared onto glass substrates by chemical bath deposition technique are irradiated with 100 MeV Ni⁸⁺ ion beams with different fluences from 1x10¹¹ to 1x10¹³ ions cm^-2. Analysis of the samples by X-ray diffraction show increase of average grain size from 11 nm for the pristine samples to 17 nm for the samples irradiated with 1x10¹¹ ions cm^-2. The grain size remains constant at higher fluences. The UV-visible optical absorption measurement also show that band gap of nanocrystalline PbS decreases from 1.9 eV for the pristine samples to 1.7 eV for the samples irradiated with fluences of 1x10¹¹ ions cm^-2 and then remains almost constant. It is observed from photoluminescence (PL) study that the PL intensity increases for irradiated samples with minimum intensity for pristine sample.

4 illus, 16 ref

009774   Chattopadhyay P;Dutta S (Electronic Science Dep, University of Calcutta, 92, A.P.C. Road, Kolkata-700 009, Email: pcelc@caluniv.ac.in) : Saturated velocity model of MESFET in the presence of interface states and interfacial layer at the gate contact. Indian J pure appl Phys 2012, 50(4), 265-71.

The saturated velocity model of a short channel MESFET has been extended by incorporating the effects of interface states and interfacial layer at the gate contact of the device. Simple analytical forms for the channel current, drain conductance and transconductance of the device are derived and they are found to be much sensitive to interface state density. The proposed model has been applied to compare the drain characteristics of Si, SiC and GaN MESFETs. For all three materials, the channel current has been found to decrease with drain voltage as the field across the channel exceeds the critical field required for velocity saturation. The decrease in the drain current yields a negative drain conductance and transconductance with respect to drain and gate voltage, respectively. The experimental results reported by the earlier researchers on GaN and SiC MESFETs are considered to compare the theory with experiment over the domain of velocity saturation. It has been found that the experimental results can be best explained on the basis of an energy distribution of interface states at the gate contact of both the devices.

6 illus, 2 tables, 32 ref

009773   Chandra S;Paul S N;Ghosh B (Physics Dep, Jadavpur University, Kolkata-700 032, Email: swarniv147@gmail.com) : Linear and non-linear propagation of electron plasma waves in quantum plasma. Indian J pure appl Phys 2012, 50(5), 314-19.

Using one-dimensional quantum hydrodynamic model, the linear and non-linear characteristics of electron plasma waves have been studied both analytically and numerically in a two-component unmagnetized dense quantum plasma with streaming motion. It is shown that quantum effect modifies the linear dispersion character of the electron plasma waves and streaming effect makes it possible the excitation of two distinct modes. To describe the non-linear behaviour, Korteweg de Vries equation is derived by using the standard reductive perturbation technique and incorporating quantum-mechanical effects. It is shown that depending on/some critical values of the quantum diffraction parameter both rarefactive and compressive type of solitons can exist in the model plasma. The structure of the solitary waves is shown to be significantly affected by the quantum plasma parameters and streaming motion.

5 illus, 27 ref

009772   Buytaert J A N;Dirckx J J J (Laboratory of Biomedical Physics, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium, Email: jan.buytaert@ua.ac.be) : Performance of 84 phase-shifting algorithms for interferometry. J Optics 2011, 40(3), 114-31.

When performing phae-shifting, phase differences in a periodic intensity profile are changed, and the resulting irradiance distributions are recorded at each step. The wanted phase cn be obtained from the arctangent of the ratio between two combinations of the observed irradiances, according to the phase-shifting algoithm (psa) used. There are many such combinations and thus different PSAS, each with specific performance and properties. We briefly discuss some error sources which might influence the performance and quality of interferometry measurements. The robustness against these error sources is strongly dependent on the PSA used. Several computer simulations on all of the 84 PSAS were carried out to confirm which algorithms perform best in the presence of some straightforward error sources.

4 illus, 1 table, 31 ref

009771   Awoga O A;Ikot A N;Akpan I O;Antia A D (Theoretical Physics Group, Physics Dep, University of Uyo, Nigeria, Email: ola.awog@yahoo.com) : Solution of schrodinger equation with exponential coshine-screened potential. Indian J pure appl Phys 2012, 50(4), 217-23.

An exact solution of the Schr”dinger equation with Coshine-screened potential by means of Nikiforov-Uvarov method has been presented. The bound state energy eigenvalues and the corresponding unnormalized wave functions expressed in terms of the associated Laguerre polynomials have been obtained. The numerical results for some selected diatomic molecules have been presented.

8 illus, 4 tables, 29 ref

009770   Arora P;Jha P;Agarwal A;Gupta A S (Time & Frequency Div, National Physical Laboratory (CSIR), , New Delhi-110 012, Email: arorap@mail.nplindia.ernet.in) : Measurement of natural linewidth of atomic transition using saturated absorption. Indian J pure appl Phys 2012, 50(5), 295-8.

Hyperfine structure of the 852 nm 6²S_1/2 → 6²P_3/2 (D2 line) transition in ¹³³Cs atoms has been investigated. Natural linewidth of the transition has been measured using saturated absorption spectroscopy. The measured value of linewidth is 5.09 MHz which is close to the literature value of 5.2 MHz. Such novel technique is easily realizable and useful for quick investigations of hyperfine structure of atomic samples in normal vapour cells.

6 illus, 13 ref

009769   Arivazhagan M;Kandasamy N K;Thilagavathi G (Physics Dep, A A Government Arts College, Musiri-621 201, Email: jjmarivu@yahoo.co.in) : Vibrational spectra, first hyperpolarizability, HOMO-LUMO analysis of 4-bromo 2-fluro anisole. Indian J pure appl Phys 2012, 50(5), 299-307.

The FTIR and FT Raman spectra of 4-bromo-2-fluoro anisole (4B2FA) have been recorded in the regions 4000-400 and 3500-50 cm^-1, respectively. The optimized geometry, frequency and intensity of the vibrational bands of 4B2FA have been obtained by ab-initio and DFT levels of theory with complete relaxation in the potential energy surface using 6-311++G basis set. A complete vibrational assignment aided by the theoretical harmonic frequency analysis has been proposed. The harmonic vibrational frequencies calculated have been compared with experimental FTIR and FT Raman spectra. The observed and the calculated frequencies are found to be in good agreement. The calculated results also show that the 4-bromo-2-fluoro anisole (4B2FA) might have microscopic Non Linear Optical (NLO) behaviour with non-zero values. A detailed interpretation of the infrared and Raman spectra of 4B2FA is also reported based on total energy distribution (TED). The calculated HOMO and LUMO energy gap shows that charge transfer occur within the molecule.

4 illus, 3 tables, 31 ref

009768   Alnour I A;Ibrahim N;Hossain I (Physics Dep, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Skudai, Malaysia, Email: aaibrahim3@live.utm.my) : Concentrations of <. Indian J pure appl Phys 2012, 50(5), 285-8.

A survey study on natural radioactivity of ²¹⁴Pb, ²¹⁴Bi in ²³⁸U series and ²⁰⁸Tl, ²²⁸Ac in ²³²Th series in granite rock collected from the state of southern Kordofan (Kadugli), Sudan has been carried out by using g-ray spectroscopy technique. The gamma-ray spectra have been measured for daughter decaying of ²³⁸U and ²³²Th series. Elemental and activity concentrations were found to be 1.41±0.02 ppm and 17.41±0.19 Bqkg^-1 for ²¹⁴Pb, 1.66±0.02 ppm and 25.60±0.21 Bqkg^-1 for ²¹⁴Bi and 9.56±0.11 ppm and 38.81±0.43 Bqkg^-1 for ²⁰⁸Tl, 8.55±0.06 ppm and 34.71±0.23 Bqkg^-1 for ²²⁸Ac, respectively. Moreover, average activity concentrations of these radio-nuclides for granite samples have been compared with the typical values of different countries

1 illus, 2 tables, 20 ref

008703   Verma D;Shakir Khan M;Zubair M (Applied Physics Dep, Z H College of Engineering & Technology, Aligarh Muslim Univ, Aligarh-202 002, Email: dpkapd@gmail.com) : Radon and its progeny measurements in dwellings of Farrukhabad city of Uttar Pradesh in Northern India. Indian J pure appl Phys 2012, 50(6), 355-7.

Radon and its progeny inside different dwellings of Farrukhabad city of Uttar Pradesh in northern India have been measured in order to calculate the Potential Alpha Energy Concentration (PAEC) and effective dose to the population of study area. The values of PAEC have been found to vary from 5.04 to 9.91 mWL with an average value of 7.19 mWL. The values of radon daughters concentration vary from 46.62 to 91.67 Bq/m³ with an average value of 66.54 Bq/m³. However, the values of effective dose found to vary from 0.80 to 1.58 mSv/yr with an average value of 1.15 mSv/y. The values of radon daughters concentration in study area were found to be below the value of 200 Bq/m³ recommended by the International Commission on Radiological Protection (ICRP). Also the values of effective dose levels were found to be lower than the average value of 2.4 mSv/y given by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR).

1 table, 18 ref

008702   Tomar S S;Tomar R (Physics Dep, S.L.P. Govt. P.G. College, Gwalior, Madhya Pradesh-474 006) : Ultrasonic method: a diagnostic tool to determine adulteration in liquid fuels. J pure appl Ultrasonics 2011, 33(1), 3-7.

An ultrasonic grating acts as a sensor to evaluate adulteration in liquids. The method on physical optics in combination ultrasonic grating has been used to diagnose adulteration in liquid mixtures for the present study. In this method separation between the diffracted dots depends upon the concentration or density or the refractive index of the adulterants. The variation of successive diffracted dots with concentration is sensitive enough to detect very small amount of adulteration. Light is diffracted due to ultrasonic grating and the separation of diffracted dots observed on the screen is a measure of adulteration in liquid mixtures.

4 illus, 5 tables, 18 ref

008701   Sunil K;Sharma B S (Physics Dep, Institute of Basic Sciences, Dr B R Ambedkar Univ, Khandari Campus, Agra-282 002, Email: k.sunil.ibs@gmail.com) : Thermoelastic properties of alkali halides at high temperatures. Indian J pure appl Phys 2012, 50(6), 387-92.

The thermoelastic properties of materials at high temperatures, specifically the thermal expansivity and the isothermal bulk modulus have been studied using the Anderson formula for thermal expansivity and the interatomic potential functions within the framework of the Born model. We have considered sixteen alkali halides with NaCl structure, and calculated their properties for a wide range of temperatures starting from room temperature up to their melting temperatures. Potential energy curves have been plotted and used to determine interatomic distances at the melting points. The results for interatomic distances, thermal expansivity and isothermal bulk modulus at different temperatures have been found to compare well with the available experimental data. The Hildebrand equation of state has been used to predict the pressure-volume-temperature relationship in case of NaCl using the Born-Mayer exponential potential function. The results,thus, obtained are found to present good agreement with the measured data.

4 illus, 3 tables, 32 ref

008700   Sun J X;Tian C X;Wang E Q;Li B C;Liu F H (Institute of Theoretical Physics, Shanxi Univ, Taiyuan, Shanxi-030 006, China, Email: fuhuliu@163.com) : Application of the multisource thermal model in pseudorapidity distributions of charged particles produced in pp (bar) or pp collisions over an energy range from 0.053 to 7 TeV. Indian J pure appl Phys 2012, 50(6), 374-9.

The pseudorapidity distributions of charged particles produced in pp(bar) or pp collisions over a center-of-mass energy range from 0.053 to 7 TeV have been studied by using the multisource thermal model. The difference between the rapidity and pseudorapidity for massive particles (pions) has been considered. The calculated results are found to be in agreement with the experimental data of the UA5, UA1, P238, CDF, CMS and ALICE Collaborations.

3 illus, 2 tables, 20 ref

008699   Suhail M H (Physics Dep, College of Science, Baghdad, Iraq, Email: mhsuhail@yahoo.com) : Structural and optical properties of ZnS, PbS, Zn_1-xPb_xS, Zn_xPb_1-xS and PbZn_xS_1-x thin films. Indian J pure appl Phys 2012, 50(6), 380-6.

The chemical spray pyrolysis technique (CSPT) to prepare ZnS, PbS, Pb_xZnl_-xS, (x = 0 to 1), PbZn_1-xS_x and Pb_xZn_1-xS, thin films with (x = 0.01, 0.02) at glass substrate, has been used. The result of X-ray diffraction obtained that the films are polycrystalline and have cubic with hkl (111) and wurtize with hkl (100) phases for ZnS films, the phase for PbS films is cubic with hkl (200) and the phases for Pb_xZn_1-xS, Pb_1-xZn_xS and PbZn_xS_1-x are cubic with hkl (200). The lattice constants (a) have been calculated as 5.939 Angstrum for PbS films, 3.36 Angstrum and 5.44 Angstrum for wurtize and cubic of ZnS films, respectively, 5.91 to 6.2 Angstrum as x varied from 0 to 1 for Zn_1-xPb_xS, 5.92Angstrum for Zn_xPb_1-xS films with x = 0.02, and 5.921 A for PbZn_xS_1-x films with x = 0.01. The absorption spectra used in the wavelength range 200-1100 nm to calculate the optical energy gap which is found to decrease with increase in the film thickness for all the films prepared by this technique. The values of energy gap have been determined and it was between (1.58-1.78 eV) for PbS films, (2.9-3.1 eV) for ZnS films. The energy gap of Zn_xPb_1-xS films in the range (2.4-2.9) eV and (2.38-2.75) eV and of Pb Zn_xS_1-x it was (1.57-1.8) eV and (1.4-1.6) eV for x = 0.02 and x = 0.01, respectively as the thickness increases. The optical constants, such as refractive index (ri) and extinction coefficient (k) increase and decrease with increase in the film thickness, respectively for all the films except ZnS films which are having inverse properties. The dielectric constants (ε_r, ε_i) have the same behaviour of refractive index (n) and extinction coefficient (k), respectively.

5 illus, 11 tables, 21 ref

008698   Subramanyam Naidu P;Ravindra Prasad K (NO, S.V.U.P.G. Centre, Kavali-524 201, Email: psnaidujb@yahoo.co.in) : Effect of potassium halides on the equilibrium of aqueous t-butanol system at 30°C-II. J pure appl Ultrasonics 2011, 33(1), 16-20.

Ultrasonic velocity and density have been measured experimentally at 30°C in t-butanol + water system at low concentrations. To this aqueous t-butanol system, small quantities of potassium halides, KC1, KBr and KI have been added and the measurements repeated. From the velocity peaks and compressibility minima, the effect of potassium halides on the clathrate structures of aqueous t-butanol system has been studied. Also by computing apparent mojar volumes and apparent molar compressibilities, ion-solvent, solute-solvent interactions are estimated in the total system.

1 illus, 2 tables, 10 ref

008697   Randey R R;Saini K K;Paul M;Sharma C P; Chander Kant;Dhayal M (NO, National Physical Lab, New Delhi-110 012, Email: kksaini@gmail.com) : Surface analysis of tungsten doped TiO₂ films and its effect on photocatalytic degradation of environmental pollutants. J Energy envir Carbon Credits 2011, 1(1), 26-41.

Nanocrystalline TiO₂ films, undoped and doped W⁶⁺ ions have been prepared on cleaned glass substrate by sol-gel route. Formation of anatase TiO₂ phase has been confirmed by XRD analysis of the samples annealed at 550°C for 5 hours. Size of nanocrystals calculated by Debye-Scherrer's formula and measured by TEM was found to decrease with increase in doping level. Average nanocrystal diameter in undoped sample is <126> 60 nm and 5 mole % W⁶⁺ ion doped sample is <126> 33 nm. SEM and AFM observation shows surface roughness of the order of the particles size in undoped as well as W⁶⁺ ion doped samples. Calculations have shown <126>50% increase kinetic efficiency of the films doped with 5mole% W⁶⁺ ions. XPS analysis revealed more oxygen deficiency and enhanced surface carbon content of the doped film. The increase photocatalytic activity of the doped film has complex dependent on the film porosity, roughness, existence of oxygen vacancies and carbon content at the surface of the W⁺⁶ ion doped film.

9 illus, 2 tables, 38 ref

008696   Palani R;Kalavathy S (Physics Dep, D.D.E., Annamalai Univ, Annamalainagar-608 002, Email: palani_physics06@yahoo.co.in) : Acoustical studies of molecular interaction in ternary liquid mixture of cresols with benzaldehyde and tetrachloromethane solutions at 303, 308 and 313 K. J pure appl Ultrasonics 2011, 33(1), 21-5.

Ultrasonic velocity (U), density (ρ) and viscosity (η) for the ternary liquid mixtures of benzaldehyde + tetrachloromethane + o-cresol, benzaldehyde + tetrachloromethane + m-cresol and benzaldehyde + tetrachloromethane + p-cresol have been measured as a function of the composition at 303, 308 and 313K. The experimental data have been used to calculate some excess acoustical parameters, such as adiabatic compressibility (β^E), free length (L_f^E) and free volume (V_f^E). The results are discussed and interpretered in terms of specific interaction predominated by hydrogen bonding.

3 illus, 2 tables, 15 ref

008695   Nath G (Physics Dep, Veer Surendra Sai University of Technology, Odisha, Email: ganesh_nath99@yahoo.co.in) : Ultrasonic study of binary mixture of acetone with bromobenzene and chlorobenzene at different frequencies. Chem Sci Trans 2012, 1(3), 510-21.

Aims to portray the nature and extent of interaction in the binary mixture of acetone with bromobenzene and chlorobenzene by computing the various acoustic parameters such as acoustic impedance (Z), isentropic compressibility (β), intermolecular free length (L_f) and their excess values at different frequencies (1 MHz, 3 MHz and 5 MHz) using a multi frequency ultrasonic interferometer over the entire range of mole fraction at temperature 303.16 K. The experimental data for sound velocity (C) and density (ρ) of the mixture have been used to compute these parameters. The variations of sound speed with frequency plays the key role to execute the variation in these parameters which is explained in terms of different intermolecular interactions present in the binary mixture. The extent of interactions existing between component molecules has been found out. In acetone-bromobenzene system the more negative values of different excess parameter suggest that the interaction between acetone-bromobenzene is more as compare to acetone-chlorobenzene system. Further a comparative study for the above acoustical parameters between two mono substituted benzene in presence of acetone at different frequencies were discussed in terms of molecular interactions.

3 illus, 8 ref

008694   Nabadwip Singh S;Arunkumar Sharma B; Nabachandra Singh A (Physics Dep, Churachandpur College, Churachandpur-795 128, Email: nabadwipsingh@yahoo.com) : Thermoluminescence of Li₂B₄O₇: Cu and La. Indian J pure appl Phys 2012, 50(6), 358-62.

Computerized Glow Curve Deconvolution (CGCD) in th framework of kinetic formalism and Various Heating Rate (VHR) methods are subjected to the glow curves of Li₂B₄O₇: Cu,La phosphor. It was observed that the trapping parameters obtained by the two methods are similar which is well-supported by statistical analysis. The curves show three peaks with the distribution of trap depth in the range 0.79-1.42 eV.

4 illus, 2 tables, 33 ref

008693   Jain S;Parashar J (Physics Dep, Samrat Ashok Technological Institute, Vidisha, Madhya Pradesh-464 001, Email: j.p.parashar@gmail.com) : Electrostatic and electromagnetic oscillations of nanoparticles in the presence of magnetic field. J Optics 2011, 40(2), 71-5.

Dispersions characteristics of electrostatic and electromagnetic oscillations of nanoparticles in the presence of a magnetic field is studied. The frequency of electrostatic mode increases with magnetic field strength. There are two modes for propagation of electromagnetic waves. The dispersion characteristics of both the modes is sensitive to magnetic field strength, nanoparticles density and size.

^ssc5 illus, 18 ref

008692   Gadani D H;Rana V A;Bhatnagar S P;Prajapati A N;Vyas A D (Physics Dep, C U Shah Science College, Ashram Road, Ahmedabad, Email: dhgadani@yahoo.com) : Effect of salinity on the dielectric properties of water. Indian J pure appl Phys 2012, 50(6), 405-10.

The complex permittivity ∈ = ∈' - j∈" of distilled water and NaCl solutions of concentrations varying from 5000 to 35000 ppm have been measured in the frequency range from 200 MHz to 1.4 GHz using a Vector Network Analyzer (VNA). The complex permittivity of saline water collected from Kanyakumari sea bank has also been measured in this frequency range. It has been observed that the dielectric constant of water decreases slowly with increase in frequency from 200 MHz to 1.4 GHz for given salinity of water. At given frequency, the dielectric constant decreases slowly with increase in salinity from 5000 to 35000 ppm. The dielectric loss of distilled water increases with increase in frequency from 200 MHz to 1.4 GHz, but for saline water it decreases with increase in frequency, over this frequency range. The decrease in dielectric loss with increase in frequency is more for higher salinity in water. The variation of complex permittivity of water with salinity and frequency is calculated using the Stogryn equations [IEEE Trans. On Microwave Theory and Techniques, August 1971, pp. 733-736] as well as with the Klein and Swift [IEEE Transactions on Antennas and Propagation, Vol. AP-25, No. l, January 1977, pp. 104-111] equations, and the results are found to be in good agreement with corresponding experimental values. The variation of emissivity with variation of salinity calculated at fixed frequencies of 0.5, 0.9 and 1.4 GHz have also been presented in the paper, which is very much useful for remote sensing applications of oceans.

8 illus, 10 ref

008691   El-Batal H A;El-Mundouh Z S;Zayed H A;Marzouk S Y;El-Komy G M;Hosny A (Glass Research Dep, National Research Center, Dokki, Cairo Egypt, Email: h_elbatakl@yahoo.com) : Optical and infrared properties of lithium diborate glasses doped with copper oxide: effect of gamma irradiation. Indian J pure appl Phys 2012, 50(6), 398-404.

A series of lithium diborate glasses containing successive CuO contents have been prepared by conventional melt annealing technique. Optical and infrared spectral properties have been measured before and after successive gamma irradiation to study the effect of gamma irradiation on the prepared glasses. Cu-doped samples show the same strong UV absorption as the undoped sample beside a characteristic broad visible band around 772 nm with marked splitting into four peaks at 614, 656, 774 and 1064 nm in higher CuO contents. Gamma irradiation of undoped lithium borate glass causes the generation of induced absorption bands but the introduction of CuO content causes some shielding behaviour towards successive gamma irradiation. Infrared absorption spectra of the undoped and CuO-doped glasses show characteristic vibrational absorption bands related to triangular and tetrahedral borate units. The addition of CuO in lithium borate glasses causes minor changes on the intensities of the IR bands but their numbers and positions are retained. The same limited effect is observed with gamma irradiation on the measured IR bands.

4 illus, 2 tables, 36 ref

008690   Choudhary S;Sengwa R J (Dielectric Research Laboratory, Physics Dep, J N V Univ, Jodhpur-342 005, Email: rjsengwa@rediffmail.com) : Characterization of dielectric dispersion and ionic conduction behaviour of acetonitrile at low frequencies. Indian J pure appl Phys 2012, 50(6), 411-14.

The complex dielectric function, ionic conductivity and impedance behaviour of acetonitrile have been investigated over the frequency range 20 Hz-1 MHz and at the temperatures 15, 30 and 45°C. The real part of complex dielectric function increases significantly with the decrease of frequency below 100 kHz, confirms the contribution of electrode polarization effect in the dielectric properties of acetonitrile at low frequencies. The real part of alternating current conductivity shows the direct current ionic conductivity plateau in the frequency range 1 kHz-1 MHz. The complex impedance plane plots have been used to separate the electrode polarization effect from the bulk acetonitriie properties. The values of temperature dependence electrode polarization relaxation time have been determined from the frequency which corresponds to the peaks observed in the dielectric loss tangent spectra. The activation energies of relaxation time, conductivity and viscosity have been evaluated from their Arrhenius plots, and discussed in relation to the ionic conduction mechanism in the pure liquid state of acetonitrile.

3 tables, 20 ref

008689   Arivazhagan M;Senthil Kumar J (Physics Dep, A A Government Arts College, Musiri-621 211, Email: jjmarivu@yahoo.co.in) : Vibrational assignment, HOMO-LUMO, first-hyperpolarizability and mulliken's charge analysis of 2,7-dinitrofluorene. Indian J pure appl Phys 2012, 50(6), 363-73.

The experimental and theoretical study on molecular structure and vibrational spectra of 2,7-dinitrofluorene (DNF) have been investigated. The FTIR and FT-Raman experimental spectra of the molecule have been recorded in the range 4000-50 cm^-1 and 3500-50 cm^-1, respectively. Making use of the recorded data, the complete vibrational assignments are made and analysis of the observed fundamental bands of molecule is carried out. The experimental determination of vibrational frequencies has been compared with those obtained theoretically from DFT quantum mechanical calculations using B3LYP/6-311+G(d,p) and 6-311++G(d,p) basis sets. The HOMO-LUMO analysis explains the charge transfer taking place within the molecule. The predicted first-hyperpolarizability value of DNF (5.5058 x 10^-30 esu) suggests that the title molecule is an attractive object for future studies of non-linear optical property. Thermodynamic properties like entropy, heat capacity and zero-point energy have been calculated for the molecule. The total energy distribution (TED) values obtained reflect the correctness of the vibrational assignments.

6 illus, 6 tables, 37 ref

007735   Vitisha Suman;Sarkar P K (Health Physics Div, Bhabha Atomic Research Centre, Mumbai-400 085, Email: vitisha@barc.gov.in) : Unfolding an under-determined neutron spectrum using genetic algorithm based Monte Carlo. Indian J pure appl Phys 2012, 50(7), 501-4.

An approach of neutron spectrum unfolding based on a stochastic evolutionary search mechanism - Genetic Algorithm is presented. A pulse height spectrum at zero degree from the nuclear reaction of incident energetic carbon ions on a thick silver target carried out at an accelerator facility is used for the unfolding. The problem is also converted to an under-determined one and is unfolded by the present approach and the output is compared with results from the standard FERDOR code. Necessity of carrying out smoothening of the obtained solution is also studied, which leads to approximation of the solution yielding an appropriate solution finally. A simple smoothening and a Monte Carlo averaging, based smoothening methods have been studied. Unfolded flux value obtained after inclusion of the smoothening criteria results in a close agreement to the output obtained from the FERDOR code.

4 illus, 8 ref

007734   Verma D;Sahu T K;Khare M;Dashora S;Khan S; Nayak M K;Sahani P K;Haridas G;Sarkar P K (Health Physics Div, Bhabha Atomic Research Centre, Mumbai-400 085, Email: dimple@rrcat.gov.in ) : Photon and neutron dose evaluation in experimental hall of Indus-1 synchrotron radiation source. Indian J pure appl Phys 2012, 50(7), 505-8.

Radiation measurement in Indus-1 experimental hall and Control Room area was performed for evaluating the photon and neutron dose rates during various operating conditions. The measurements were carried out using VICTOREEN 451 P and LUDLUM Model 2363 survey meter for photon and neutron dose rate measurement, respectively. From the measurements, it was seen that during Indus-) injection, maximum photon dose rate of 410 μSv/h and maximum neutron dose rate of 15.9 μSv/h have been observed at the hot spots (at pre-mirror locations of HRVUV Beam Line and Photo Physics Beam Line). At experimental station of the beam lines, the neutron dose rates observed were in the range 1.0-3.4 μSv/h whereas the photon dose rates were up to 0.9 μSv/h. During Indus-1 storage condition, the radiation levels were near background levels except at one of the hot spots (pre-mirror. Photo Physics Beam Line) where photon and neutron dose rates observed were 6.3 μSv/h and 45.1 μSv/h, respectively. During Indus-2 injection, neutron dose rates ranging from background to 3.3 μSv/h were observed in the sitting area at experimental station whereas photon dose rate was noticed up to 0.4 μSv/h. For the control room area, neutron dose rates up to a maximum of 3 μSv/h were observed during Indus-1 injection only. During other operation modes, dose rates in control room are of background level. In view of the data during injection mode of Indus-1, entry prohibition is re-confirmed to the experimental hall whereas it is restricted during the storage (user) mode. Details of the measurements and results are presented in the paper.

1 illus, 2 tables, 2 ref

007733   Uwamino Y;Sakamoto H;Higurashi-Hirunuma R; Mukai H;Fukuda H;Akashio A (Nishina Center for Accelerator-Based Science, RIKEN, 2-1, Hirosawa, Wako, Saitama 351-0198, Japan, Email: uwamino@riken.jp) : State of the RIKEN radioisotope beam factory. Indian J pure appl Phys 2012, 50(7), 442-5.

RIKEN Radioisotope Beam Factory (RIBF) consisted of a heavy ion linac (RJLAC), a small cyclotron (AVF), four ring cyclotrons (RRC, fRC, IRC and SRC), and projectile-fragment separators (RIPS and BigRIPS) when its operation was started at the end of 2006. SRC is the final stage superconducting cyclotron and its maximum energy is 400 MeV/nucleon for lighter ions of hydrogen to Ar and 350 MeV/nucleon for heavier ions up to uranium. A new injector linac (RILAC-II) with a 28 GHz superconducting ECR ion source was completed in March, 2011 and beam intensities of 1 pμA for ⁴He and 3 pnA for ²³⁸U were achieved. Polarized deuteron beam is also available. New developed electron-nucleus scattering equipment is under construction. It is called SCRIT (Self-Confining Radioisotope Ion Target) and consists of a 150-MeV microtron and a 700-MeV synchrotron storage-ring. It will realize the electron scattering experiment with unstable nuclides for the first time. In spite of the big earthquake on March 11, 2011, damages on the accelerators were quite small, that is, vacuum leaks were found at two points in the transport lines. They were repaired, and the experiment was started in June, 2011.

4 illus, 1 table, 6 ref

007732   Upadhyay T C;Joshi D (Physics Dep, H N B Garhwal Univ, Srinagar (Garhwal), Uttarakhand-246 174, Email: utrilok@yahoo.in) : Temperature dependence of antiferroelectric mode frequency, dielectric contant and loss tangent of ADP crystal in presence of electric field. Indian J pure appl Phys 2012, 50(3), 167-74.

A four sub-lattice pseudospin lattice coupled mode model modified with third and fourth-order phonon anharmonic interaction terms and external electric field terms has been considered for ADP crystal. Expressions for shift, width, renormalized antiferroelectric mode frequency, dielectric constant and loss tangent have been evaluated. Double-time thermal Green's function method has been used for derivation. Fitting the values of model parameters in expressions, the temperature dependence of antiferroelectric mode frequency dielectric constant and loss tangent has been calculated in the presence of electric field. Theoretical results agree well with data reported by Okada et al. [Okada K, Sugie E, Kanno K & Tada K,JPhys Soc Japan, 43 (1977) 557.]

8 illus, 1 table, 45 ref