017487   Zheng G;Xu L;Chen Y;Su W;Liu Y (Opticas and Photonic Technology Laboratory, Nanjing Univ of Information Science and Technology, Nanjing 210044, China) : Beam filter and splitter based on surface plasmon propagation in ring metal heterowaveguide. Pramana J Phys 2014, 83(6), 995-1002.

Surface plasmon polaritons (SPPs) beam filter (BF) and beam splitter (BS) constructed using metal heterostructures are proposed and demonstrated numerically. Both structures have a ring metal heterowaveguide, which is constructed by a metal cylinder and a ring dielectric cladding. The two-dimensional finite-difference time-domain (2D-FDTD) method is employed to study the properties of the proposed BF and BS, and the results show that SPPs can effectively propagate on bended plasmonic waveguides with dielectric claddings. By introducing dielectric and plasmonic waveguides on both sides of the resonant ring, SPPs can be efficiently excited at the output of the waveguide ring resonator (WRR) through mode coupling. The planar metal heterostructures provide a way for constructing various nanoscale counterparts of conventional planar integrated devices such as filters, splitters, resonators, sensors, optical switches, and so on.

6 illus, 17 ref

017486   Sonone R L;Jain S R (Physics Dep, Pune Univ, Pune-411 007, Email: vaidehisonone@gmail.com) : Dynamics, stability analysis and quantization of β-fermi-pasta-ulam lattice. Pramana J Phys 2014, 83(6), 925-44.

Study the well-known one-dimensional problem of N particles with nonlinear interaction. The β-Fermi-Pasta-Ulam model is the special case of quadratic and quartic interaction potential among nearest neighbours. We enumerate and classify the simple periodic orbits for this system and find the stability zones, employing Floquet theory. We quantize the nonlinear normal modes and construct a wavefunction for what we believe is a primitive nonlinear analogue of a 'phonon'.

9 illus, 5 tables, 28 ref

017485   Saha A;Amritkar R E (Physical Sciences Dep, Indian Institute of Science Education and Research, Kolkata-741 252, Email: arindam1002@iiserkol.ac.in) : Dependence of synchronization frequency of kuramoto oscillators on symmetry of intrinsic frequency in ring network. Pramana J Phys 2014, 83(6), 945-53.

Kuramoto oscillators have been proposed earlier as a model for interacting systems that exhibit synchronization. In this article, we study the difference between networks with symmetric and asymmetric distribution of natural frequencies. We first indicate that synchronization frequency of oscillators in a completely connected network is always equal to the mean of the natural frequency distribution. In particular, shape of the natural frequency distribution does not affect the synchronization frequency in this case. Then, we analyse the case of oscillators in a directed ring network, where asymmetry in the natural frequency distribution is seen to shift the synchronization frequency of the network. We also present an estimate of the shift in the frequencies for slightly asymmetric distributions.

4 illus, 13 ref

017484   Ray H (NO, National Institute of Technical Teachers' Training and Research Kolkat, Salt Lake City, Kolkata-700 106, Email: hasi.ray1@gmail.com) : Two atoms scattering at low and cold energies. Pramana J Phys 2014, 83(6), 907-14.

A modified static-exchange model is developed to study the collision of an atom with another atom. It includes the effect of long-range dipole-dipole van der Waals interaction between two atoms in addition to the exact effect of short-range force due to Coulomb exchange between two system electrons. Both these interactions dominate at colder energies. The system is treated as a four-centre problem in the centre-of-mass frame. The present ab-initio model is useful to study the two-atomic collisions at low energies, as well as cold energies. The new code is applied to study the scattering of positronium (Ps) by hydrogen (H), both in their ground states.

3 illus, 1 table, 23 ref

017483   Rastgoo S;Golshan M M (Physics Dep, College of Sciences, Shiraz Univ, Shiraz 71454, Iran, Email: golshan@susc.ac.ir) : Spin-spin entanglement in moving frames: properties of negativity. Pramana J Phys 2014, 83(6), 915-23.

In the present article, we use negativity to investigate the entanglement between two massive particles in the spin degrees of freedom, as seen by moving observers. Assuming that the occurrence of spin-momentum states is determined by Gaussian probability distributions, we show that the degree of entanglement monotonically descends to a diminishingly small value at high rapidities. We further report, how the characteristics of this behaviour vary as the widths of distributions change. In particular, the degree of maximally entangled spin-spin states, resulting from equal distribution widths, is shown to exhibit extrema, depending on the width, at certain rapidities. The material presented in this paper then supports the idea that, for relativistic particles, a consistent reduced spin density (from which the negativity is derived) is impossible to construct.

2 illus, 39 ref

017482   Pandey H K;Singh S K;Singh P R (Physics Dep, Patna Women's College, Patna-800 001, Email: simeshi_123@rediffmail.com ) : Classical approach to the melting of a nanorod. Int J Nano Sci Technol 2014, 3(2), 21-7.

Melting point depression and enhancement of nanomaterials have been found to depend on size, dimension and surface properties of the nanomaterials. Ours is a phenomenological model based on classical considerations regarding melting of nanomaterials. We have considered a nanorod and using a simple minded approach of cohesive binding energy observed that the melting point of the nanorod gets depressed as the size goes down. Further, to illustrate the phenomena, we have adopted a classical thermodynamic approach which is mainly based on Gibbs energy of a nanorod. We have minimized the Gibbs energy for the nanosystem in different phases and calculated and analyzed the results for the melting point of the nanorod. The results of our models are consistent with both of experimental results and other thermodynamic models.

9 illus, 12 ref

017481   Naveen Kumar K;Buddhudu S (Physics Dep, Sri Venkateswara Univ, Tirupati-517 502, Email: knaveenphy@gmail.com) : Enhanced photoluminescence of Mn<. Proc Indian Natn Sci Acad 2014, 80(2), 345-54.

Polymer blended films of PEO+PVP and singly doped and co-doped with Mn^{2+ and Tb3+ ions have been synthesized by solution casting method. Structural, thermal and optical properties of these films have been carried out. Thermal stability of these films has been investigated based on the measurement of TG-DTA profiles. Raman analysis demonstrates the complex formation of the polymer with the dopant ions. The optical absoption spectra of Mn2+ and Tb3+ seperately doped polymers exhibits characteristic bands in octahedral symmetry. From the emission spectrum, two emission bands at 510nm (green) and 614nm (red) are attributed to the 4T₁ 6A₁, and 4A₁ 6_{A1 transition of Mn2+}:PEO+PVP polymer films under 370nm excitation. In Tb3+ doped PEO+PVP polymer samples exhibit green emission at 546 nm (green) due to a transition of (5D₄ 7F₅) under 370nm excitation. The enhanced red emission at 614nm of Mn2+ ions is attributed to an effective energy transfer of Tb3+ Mn2+ ions in the co-doped blended polymer film, which has been evidenced from the measurement of luminescence spectra and emission decay dynamics. These polymeric materials are suggested as bright visible colour luminescent materials.}

8 illus, 27 ref

017480   Maibam J;Kabita K;Sharma BI;Bhattacharjee R; Thapa R K;Brojen Singh R K (Physics Dep, Assam University Silchar, Silchar-788 011, Email: indraofficial@rediff.com) : Density Functional Theory: band structure. Invertis J renewable Energy 2015, 5(1), 30-3.

Density functional theory (DFT) methods are the most widely spread ab initio methods in computational material science and solid state physics. DFT starts with a consideration of the entire electron system. The wave function of the electron system is a function of 3N variables. However, within DFT all aspects of the electronic structure of the system of interacting electrons in an external potential are completely determined by the electronic charge density p(r). The charge density is a function of only three variables. As an example, electronic band structure of VC and VN are calculated using DFT.

2 illus, 8 ref

017479   Madhurima V (Central Univerity of Tamil Nadu, , Thiruvarur-610 001, Email: madhurima.v@gmail.com) : Molecular interactions and designer materials. Invertis J renewable Energy 2015, 5(1), 34-40.

Weak intermolecular interactions such as Hydrogen bonds are responsible for many interesting properties exhibited by soft matter since the bond energies are comparable to thermal energy at room temperature. Insights into these bonds and the bonding mechanisms can be used to design materials that possess specific properties such as high dielectric permittivity, tailor made interactions in biological systems etc. This calls for the characterization of the molecules followed by appropriate design. Three current research interests (a) intermolecular interactions in soft matter (b) interactions between soft matter and substrates and (c) design of materials with specific properties are discussed in some detail.

3 illus, 1 table, 25 ref

017478   Kundu R (Physics Dep, R.K.M.V.C. College, Rahara, Kolkata-700 118, Email: rajenkundu@yahoo.com) : Nucleonic helicity distributions revisited with an emphasis on their evolutions and twists. Pramana J Phys 2014, 83(6), 963-74.

In this work, authors uphold and extend the formalism advocated by us more than a decade ago in order to extract information on various distribution functions describing nucleonic helicity structure and calculate a complete set of splitting functions relevant for their quantum chromodynamics (QCD) evolutions using light-front Hamiltonian perturbation theory in light front gauge A^{+ = 0. Twist-two structures of the helicity distributions are self-evident in our calculation. Sum rules associated with these helicity distributions are also verified in a frame-independent way.}

10 ref

017477   Khasare S B (Physics Dep, Science College, Congress Nagar, Nagpur-440 012, Email: shailendra.khasare@yahoo.com) : Flexible equation of state for a hard sphere and lennard-jones fluid near critical temperature. Pramana J Phys 2014, 83(6), 955-62.

Author uses the condition in terms of contact point radial distribution function G(σ, λ(η_c, α)) containing the self-consistent function λ(η_c, α) and condition of continuity at σ/2 =contact point, to determine equation of state, (EoS). Different EoSs in terms of built-in parameter,m, can be obtained with a suitable choice of λ(η_c, α) and the present EoSs have less r.m.s. deviation than Barker-Henderson BH2 for LJ fluids, and results are much closer to molecular dynamics (MD) simulations than expectations and reproduce the existing simulation data and present EoS for LJ potential, with the help of a set of minimum single-scaled parameter, a0(η_c, α) for a given reduced temperature, T* = (1/β∈) = 1.4, 2, 3, 4, 5, 6. It has been found that parameter α = 1.059128388 can be used to fix up the critical temperature parameter T_c = 1.3120(7) to that of a computer simulation result.

1 illus, 8 tables, 24 ref

017476   Khan N H;Ahsan M H;Chowdhury M A H (Physics Dep, Sylhet Government College, Sylhet, Bangladesh) : Potentiality of sunlight observed in CsI(TI) crystal. Ultra Scient phys Sci-Sect B 2014, 26(2), 153-8.

The effect of sunlight on Φ 2.54 x 2.54 cm^{2 CsI(Tl) crystal of Tl concentration 500 ppm has been studied. Long period of sunlight exposure can induce new defects and reduce the transparency of the crystal. The optical absorption spectra in the infrared region are mostly affected rather than in the visible region. After the exposure of sunlight the rate of optical bleaching and optical darkening effect on CsI(Tl) crystal is almost same.}

6 illus, 13 ref

017475   Khan M D;Naeem I;Imran M (Mathematics Dep, School of Science and Engineering, Lahore Univ of Management Sciences, Lahore Cantt 54792, Pakistan, Email: imran.naeem@lums.edu.pk) : Analytical solutions of time-space fractional, advection-dispersion and Whitham-Broer-Kaup equations. Pramana J Phys 2014, 83(6), 885-906.

In this article, author study time-space fractional advection-dispersion (FADE) equation and time-space fractional Whitham-Broer-Kaup (FWBK) equation that have significant roles in hydrology. We introduce suitable transformations to convert fractional-order derivatives to integerorder derivatives and as a result these equations transform into partial differential equations (PDEs). Then the Lie symmetries and the corresponding optimal systems of the resulting PDEs are derived. The symmetry reductions and exact independent solutions based on optimal system are investigated which constitute the exact solutions of original fractional differential equations.

37 ref

017474   Kailas S;Mahata K (Nuclear Physics Div, Bhabha Atomic Research Centre, Mumbai-400 085, Email: kailas@barc.gov.in) : Charged particle-induced nuclear fission reactions - progress and prospects. Pramana J Phys 2014, 83(6), 851-84.

The nuclear fission phenomenon continues to be an enigma, even after nearly 75 years of its discovery. Considerable progress has been made towards understanding the fission process.Both light projectiles and heavy ions have been employed to investigate nuclear fission.An extensive database of the properties of fissionable nuclei has been generated. The theoretical developments to describe the fission phenomenon have kept pace with the progress in the corresponding experimental measurements. As the fission process initiated by the neutrons has been well documented, the present article will be restricted to charged particle-induced fission reactions. The progress made in recent years and the prospects in the area of nuclear fission research will be the focus of this review.

15 illus, 1 table, 120 ref

017473   Goswami D K (Physics Dep, Indian Institute of Technology Guwahati, Guwahati-781 039, Email: dkg@iitg.ernet.in) : Organic semiconductor materials for future electronics. Invertis J renewable Energy 2015, 5(1), 41-6.

Organic semiconductors are very promising candidates as starting materials for the manufacture of cheap, large area and flexible electronic components such as transistors, diodes and sensors on a scale ranging from micro to nano. However, there are lots of challenges in this field that receive substantial attention from researchers in recent years. Due to poor van der Waals interaction between molecules, electrical conductivity of these materials is not as high as other materials such as Si, Ge etc which are extensively being using in microelectronic industries. Nevertheless, stability of these materials has been another issue that needs to be improved through research and development. In spite of all these, these molecules show promise to be competitive candidates to replace some of the electronic devices that we are using present days. Over the years, tremendous progress has been achieved. However, much more of the work demonstrated in the laboratory needs to be translated into reliable and reproducible products, which can be manufactured cheaply. In this article, I intend to describe the important electronic devices based on organic semiconductors with specific focusing on the challenges and advantages.

2 illus, 32 ref

017472   Faye M;Mbow C;Bassirou B A (Laboratory of Semiconductors and Solar Energy, Physics Dep, Faculty of Science and Technology University, Cheikh Anta DIOP-Dakar-Senegal, Email: fayendiouma@yahoo.fr) : Development a numerical model applicable to inorganic and organic solar cells based on silicon in the presence of excitons. Curr Trends Technol Sci 2015, 4(2), 491-7.

Solar cell under monochromatic illumination by the front face and subjected to a heat insulation by the back face in permanant regime is studied. The continuity equations for electrons and excitons coupled and the heat, which govern the generation-recombination and diffusion mechanisms have been solved by a numerical approach based on the finished volumes method.These mechanisms are analyzed through the profile of the density total photocurrent, calculated for different values of the excitatrice wavelength and the volume and surface conversion coefficients which respectively depend on exciton dissociation field and the average temperature. The effects of the heating factor and the number of Fourier on the electron and exciton particule current were analyzed. In the end, a comparison between the electron and exciton particule current calculated as functions of two forms of volume coupling coefficient has also been proposed. This study allowed us to achieve our objective, namely the development of a numerical model applicable to inorganic and organic solar cells.

9 illus, 6 tables, 12 ref

017471   Emamuddin M;Mamun A A (Post Graduate Education, Training and Research Centre, National Univ, Gazipur 1704, Bangladesh) : Effect of positive dust mass on instability in four-component magnetodustyplasma in the presence of polarization force. Pramana J Phys 2014, 83(6), 1015-24.

A theoretical investigation has been carried out on the growth rate of instability of the low-frequency electrostatic waves in a partially ionized four-component magnetodustyplasma in the presence of polarization force. Utilizing the method of linear mode analysis, the results of investigation have been presented. The findings of the investigation reveal that the polarization force, the external magnetic field and the dust temperature have a tendency to destabilize the system by increasing the growth rate of instability. On the other hand, the positive dust mass causes the instability growth rate to decrease, thereby stabilizing the system.

4 illus, 48 ref

017470   Dheeraj Pratap;Mandal P;Anantha Ramakrishna S (Physics Dep, Indian Institute of Technology Kanpur, Kanpur-208 016, Email: pdheeraj@iitk.ac.in) : Plasmonic properties of gold-coated nanoporous anodic alumina with linearly organized pores. Pramana J Phys 2014, 83(6), 1025-33.

Anodization of aluminium surfaces containing linearly oriented scratches leads to the formation of nanoporous anodic alumina (NAA) with the nanopores arranged preferentially along the scratch marks. NAA, when coated with a thin gold film, support plasmonic resonances.Dark-field spectroscopy revealed that gold-coated NAA with such linearly arranged pores shows a polarization-dependent scattering, that is larger when the incident light is polarized parallel to the scratch direction than when polarized perpendicular to the scratch direction. Fluorescence studies from rhodamine-6G (R6G) molecules dissolved in polymethylmethacrylate (PMMA) and deposited on these NAA templates showed that fluorescence can be strongly enhanced with the bare NAA due to multiple light scattering in the NAA, while fluorescence from the molecules deposited on gold-coated NAA is strongly quenched due to the strong plasmonic coupling.

4 illus, 35 ref

017469   Das R;Shukla M K (School of Physical Sciences, National Institute of Science Education and Research, Bhubaneswar-751 005, Email: ritwick.das@niser.ac.in) : Measurement of nonlinear refractive index in open-aperture Z-scan experiments. Pramana J Phys 2014, 83(6), 985-94.

Presents an experimental study on measurement of nonlinear refractive index (n₂) of organic liquids when the thermo-optic effects manifest into large nonlinear phase shifts (Δφ₀) in an open-aperture Z-scan configuration. Although we do not obtain the familiar peak-valley normalized transmittance curve as in the case of closed-aperture Z-scan technique, we use a theoretical model using Gaussian beam decomposition (GD) technique to estimate the value of n₂. Using this recipe, we obtain the nonlinear refractive index n₂ = -(4.90 ± 1.20) x 10^{-15 cm2/W for toluene (organic solvent) and n₂ = -(10.60 ± 2.10) x 10-15 cm2/W for an organic polymer solution (10-4 Min toluene). By carrying out absorption measurements directly with an unfocussed Gaussian beam, we found nonlinear absorptions β_tol = (2.42 ± 0.20) x 10-13 m/W and β_poly =(2.79 ± 0.24) x 10-13 m/W which are close to the expected results.}

4 illus, 20 ref

017468   Das A K;Buzarbaruah A K;Bardaloi S (Arya Vidyapeeth College, , Guwahati-781 016, Email: akdas09@yahoo.com) : Structural and optical studies of ZnS & ZnS-Ni nano materials. Invertis J renewable Energy 2015, 5(1), 6-10.

The behavior of doped and undoped nano-particles find a great deal of interest among the researchers for its number of application in opto-electronic and semi-conductor devices. ZnS nano-crystals were grown into poly-vinyl alcohol matrix by chemical route at different weight percentage. Optical properties of both undoped and doped with ZnS nano-crystalline compounds were studied. The nano structure was characterized with the help of X-ray diffraction (XRD) and Hi- resolution Transmission Electron Microscopy (HRTEM). Surface morphology was studied with the help of Scanning Electron Microscopy (SEM). Average particle size of ZnS and ZnS-Ni were found to be 5 and 11 nm in TEM, while that obtained from XRD was about 2.28-2.49 nm. Peak of Photo-luminescence (PL) emission spectra was found at 393 nm and another peak at 403 nm corresponding to dopant 0.5 and 1.0 at room temperature. Energy dispersive X-ray fluorescence (EDX ) spectra showed presence of Zn, S, & Ni with 67.92, 27.50 & 4.58 weight respectively. These data showed successful doping with Ni. Optical absorption studies were carried out with UV- VIS Spectrophotometer and showed a strong absorbance at wavelel1gth 400 nm with a tendency towards blue shift. Selected area electron diffraction (SAED) showed a set of three well defined rings corresponding to planes 111,220,311 which tallied well with the JCPDS card No. 05-0566.

7 illus, 1 table, 11 ref

017467   Chakrabarti A;Naik V;Bandyopadhyay A;Bhandari R (Variable Energy Cyclotron Centre, Atomic Energy Dep, , 1/AF, Bidhannagar, Kolkata-700 064, Email: alok@vecc.gov.in) : Rare ion beams - the new road to understand the universe. Curr Sci 2015, 108(1), 22-9.

The last three decades have seen enormous progress in our ability to produce new nuclei. Driven by the first construction of powerful heavy-ion and light-ion accelerators and more recently, with the advent of rare isotope beams-also called radioactive ion beams(RIBs), the field of low energy nuclear physics is now vibrant with new possibilities. On one hand, the community now under-stands the nucleus and its central role in the creation of elements in the universe with more confidence, while on the other, new and surprising discoveries of nuclear halo, new magic numbers and regions of deformation, to name a few, entice us to probe for more. RIBs with their promise of making accessible hitherto unexplored regions of the nuclear chart and enhanced intensity for already syn-thesized nuclei has clearly emerged as the frontier of low energy nuclear physics. Apart from nuclear physics and astrophysics, RIBs open up new areas in materials research and biology, and provide an alternative route for medical isotope production. Further, the accelerator technology needed for producing these beams has led to the development of particle therapy machines for treatment of cancer and ion beam applications in industry. This article reviews the present scenario of physics and technology of RIBs and discusses VECC's efforts and contribution in this field and future plans vis-…-vis the up coming ANURIB project.

7 illus, 41 ref

017466   Bayram T;Yilmaz A H (Physics Dep, Sinop Univ, 57000 Sinop, Turkey, Email: tbayram@sinop.edu.tr) : Shape of Te isotopes in mean-field formalism. Pramana J Phys 2014, 83(6), 975-83.

The systematic investigation of ground-state shape evolution from γ -unstable O(6) to spherical U(5) for even-even ^{112-134Te has been presented by using the quadrupole momentconstrained Hartree-Fock-Bogoliubov (HFB) method. By examining potential energy curves of Te isotopes, it has been suggested that 124Te nucleus may hold E(5) symmetry.}

2 illus, 4 tables, 53 ref

016464   Sen D (NO, , FE 38, Salt Lake, Kolkata-700 106, Email: debashissen59@gmail.com) : Uncertainty relations in quantum mechanics. Curr Sci 2014, 107(2), 203-18.

Notion of uncertainty in the description of a physical system has assumed prodigious importance in the development of quantum theory. Overcoming the early misunderstanding and confusion, the concept grew continuously and still remains an active and fertile research field. Curious new insights and correlations are gained and developed in the process with the introduction of new 'measures' of uncertainty or indeterminacy and the development of quantum measurement theory. In this article we intend to reach a fairly uptodate status report of this yet unfurling concept and its interrelation with some distinctive quantum features like nonlocality, steering and entanglement/inseparability. Some recent controversies are discussed and the grey areas are mentioned.

112 ref

016463   Sahu K C (Chemical Engineering Dep, Indian Institute of Technology Hyderabad, Yeddumailaram-502 205, Email: ksahu@iith.ac.in) : Review on double-diffusive instability in viscosity stratified flows. Proc Indian Natn Sci Acad 2014, 80(3), 513-24.

This is a review of the previous work conducted on the double-diffusive effect in viscosity stratified systems. Two configurations are considered which are supposed to be stable in the context of single-component flows. The flow in these configurations is shown to be unstable in the presence of double-diffusive effect. A new mode of instability due to the double-diffusive effect was found, and a rich variety of instability patterns are observed in the direct numerical simulations of such flows.

^iia8 illus, 32 ref

016462   Hajamalala A M (NO, Laboratory of Applied Physics of the Univ of Fianarantsoa, Madagascar, Email: hajamalalaa@yahoo.fr) : Thermal performance of a low-concentration ethanol stove without pressure system. Curr Sci 2014, 107(2), 289-96.

Reported here the thermal performance of a new burner running on low-concentration ethanol (50°GL) without pressure system. The experimental method based on the water boiling point of water developed by Shell Foundation, consists of three phases of test used to study the performance of the stove. Test and calculation results show that the time to boil 2.5 1 of water is 19.6 min in cold start and 18.4 min in hot start. The specific consumption is 25.55 g/1 for the boiling task and 29.4 g/1 for the simmering task. The thermal efficiency calculation of the stove is 55.75% in high power and 58.3% in simmer with a turndown ratio of 2.24. The average thermal output of the stove is from a high of 1575 W to a low of 694 W. The optimal thermal output is 694 W, with a thermal efficiency of 59%. The results show that the burner can transform gradually the low ethanol-water mixture of 50% (w/w) to a vapour of ethanol-water mixture concentration of 68.55% (w/w) in cold start, 73.71% (w/w) in hot start and 68.47% (w/w) in simmer. Improving the nature of the burner components helps improve the performance of the stove and also has an impact on its lifespan. The performance of the stove depends on the variation of the concentration of ethanol fuel during the test. The experimental study showed that the stove running on 50% v/v ethanol-water mixture is a no smoking stove, with no danger of fires.

7 talbles, 16 ref

016461   Chatterjee R;Sinha S K (NO, Central Ground Water Board, 6-A, Jhalana Doongri, Jaipur-302 017, Email: rana_3b@yahoo.co.in) : Water resources database - development and management. Proc Indian Natn Sci Acad 2014, 80(3), 713-30.

Data generation, maintenance and dissemination are key components of management of natural resources including Water Resources. In India, Water Resources database in being maintained mainly by Central and State Government agencies. Some private initiatives are also in vogue. The information are disseminated both in paper form through Yearbook, Reports etc. and also through various web portals. Some of the information like rainfall etc. are priced. Government of India has formulated a Hydro-meteorological Data Dissemination Policy (2013). According to this policy, most of the water related information to this policy, most of the water related information are open to public domain and available free of cost, except for the data in some country bordering areas which have been categorized as Classified information and for restricted official use. The water resources database system needs to be further strengthened by developing an integrated and interlinked database system which permits details to be accessed at all levels.

^iia2 illus, 5 tables, 19 ref

015502   Vipin Kumar;Enamullah;Upendra Kumar;Setlur G S (Physics Dep, Indian Institute of Technology Guwahati, Guwahati-781 039, Email: k.vipin@iitg.ernet.in) : Coherent nonlinear electromagnetic response in twisted bilayer and few-layer graphene. Pramana J Phys 2014, 83(4), 597-617.

The phenomenon of Rabi oscillations far from resonance is described in bilayer and few-layer graphene. These oscillations in the population and polarization at the Dirac point in n-layer graphene are seen in the nth harmonic termin the external driving frequency. The underlying reason behind these oscillations is attributable to the pseudospin degree of freedom possessed by all these systems. Conventional Rabi oscillations, which occur only near resonance, are seen in multiple harmonics in multilayer graphene. However, the experimentally measurable current densityexhibits anomalous behaviour only in the first harmonic in all the graphene systems. A fully numerical solution of the optical Bloch equations is in complete agreement with the analytical results, thereby justifying the approximation schemes used in the latter. The same phenomena are also described in twisted bilayer graphene with and without an electric potential difference between the layers. It is found that the anomalous Rabi frequency is strongly dependent on twist angle for weak applied fields - a feature absent in single-layer graphene, whereas the conventional Rabi frequency is relatively independent of the twist angle.

7 illus, 1 table, 39 ref

015501   Vinodkumar P C (Physics Dep, Sardar Patel University, Vallabh Vidyanagar-388 120, Email: p.c.vinodkumar@gmail.com) : Heavy flavour hadron spectroscopy. Pramana J Phys 2014, 83(5), 773-82.

A comprehensive overview and some of the theoretical attempts towards understanding heavy flavour hadron spectroscopy are presented. Apart from the conventional quark structure (quark, antiquarks structure for the mesons and three-quarks structure of baryons) of hadrons, multiquark hadrons the hadron molecular states etc., also will be reviewed. Various issues and challenges in understanding the physics and dynamics of the quarks at the hadronic dimensions are highlighted. Looking into the present and future experimental prospects at different heavy flavour laboratories like BES-III, CLEO-c, BaBar, Belle, LHC etc., the scope for theoretical extensions of the present knowledge of heavy flavour physics would be very demanding. In this context, many relevant contributions from the forthcoming PANDA Facility are expected. Scopes and outlook of the hadron physics at the heavy flavour sector in view of the future experimental facilities are highlighted.

60 ref

015500   Vijaya Kumar K B (Physics Dep, Mangalore University, Mangalagangothri-574 199, Email: kbvijayakumar@yahoo.com) : Spin polarizability of hyperons. Pramana J Phys 2014, 83(5), 783-98.

Review the recent progress of the theoretical understanding of spin polarizabilities of the hyperon in the framework of SU(3) heavy baryon chiral perturbation theory (HBChPT). We present the results of a systematic leading-order calculation of hyperon Compton scattering and extract the forward spin polarizability (χ0) of hyperons. The results obtained for χ0 in the case of nucleons agree with the known results of SU(2) HBChPT when kaon loops are not considered.

1 illus, 2 tables, 67 ref

015499   Thirunavukkarasu A;Karunathan R;Mallika J; Sathyanarayanamoorthi V (Physics Dep, K S Rangasamy College of Technology, Tiruchengode, Namakkal-637 215, Email: sathyanarayanamoorthi@yahoo.co.in) : Vibrational and quantum chemical analysis of 3-methyl-2,6-diphenyl piperidin-4-one using HF and DFT methods. Indian J pure appl Phys 2014, 52(10), 653-70.

Characterization of 3-methyl-2,6-diphenylpiperidin-4-one (MDPO) by quantum chemical calculations and spectral techniques has been performed with spectroscopic investigations like FT-IR, FT-Raman and UV techniques. Molecular geometries, FT-IR spectrum (4000-400 cm^{-1) and FT-Raman spectrum (4000-100 cm-1) in solid phase was recorded. The structural and spectroscopic data of the molecule were obtained from HF and B3LYP with 6-311++G(d,p) levels using density functional theory(DFT). The stability and intra-molecular charge transfer have been analyzed by the detailed natural bond orbital (NBO) analysis. The charge transfer occurring in the molecule was verified and found to be stable from smaller energy gap by HOMO-LUMO analysis. Atomic population analysis reveals the percentage of electron distribution in s-and p-subshells. The first order hyperpolarizability of the investigated molecule has been studied theoretically. The calculated results were applied to simulated infrared and Raman spectra of the title molecule which show good agreement with observed spectra.}

10 illus, 10 tables, 40 ref

015498   Sugathan P et al (NO, Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi-110 067, Email: sugathan@iuac.res.in) : Neutron detector array at IUAC: Design features. Pramana J Phys 2014, 83(5), 807-15.

Characteristics and performance of the newly commissioned neutron detector array at IUAC are described. The array consists of 100 BC501 liquid scintillators mounted in a semispherical geometry and are kept at a distance of 175 cm from the reaction point. Each detector is a 5'' x 5'' cylindrical cell coupled to 5'' diameter photomultiplier tube (PMT). Signal processing is realized using custom-designed home-made integrated electronic modules which perform neutron-gamma discrimination using zero cross timing and time-of-flight (TOF) technique. Compact custom-built high voltage power supply developed using DC-DC converters are used to bias the detector. The neutrons are recorded in coincidence with fission fragments which are detected using multi-wire proportional counters mounted inside a 1m diameter SS target chamber. The detectors and electronics have been tested off-line using radioactive sources and the results are presented.

6 illus, 20 ref

015497   Suda T (Research Center for Electron-Photon Science, Tohoku University, 1-2-1 Mikamine, Sendai, 982-0826, Japan, Email: suda@lns.tohoku.ac.jp) : Electron scattering for exotic nuclei. Pramana J Phys 2014, 83(5), 739-47.

A brand-new electron scattering facility, the SCRIT Electron Scattering Facility, will soon start its operation at RIKEN RI Beam Factory, Japan. This is the world's first electron scattering facility dedicated to the structure studies of short-lived nuclei. The goal of this facility is to determine the charge density distributions of short-lived exotic nuclei by elastic electron scattering. The first collision between electrons and exotic nuclei will be observed in the year 2014.

5 illus, 17 ref

015496   Suchiang D;Joseph Jeremiah J;Jyrwa B M (Physics Dep, Tura Government College, Tura-794 001, Email: bjyrwa@gmail.com) : Calculation of excitation functions of the <. Pramana J Phys 2014, 83(4), 545-55.

The cross-sections for the formation of ^{54,56,57,58Co in the 54,56,57,58Fe(p, n) reaction from threshold to 30 MeV protons have been theoretically calculated using the TALYS-1.4 nuclear model code, whereby we have studied major nuclear reaction mechanisms, including direct, preequilibrium and compound nuclear reaction. Subsequently, the level density and shell damping parameters have been adjusted and at the same time, the odd-even effects are well comprehended. The excitation functions have been compared with experimental nuclear data. It is observed that the theoretical cross-sections match fairly well. Proton-induced reaction cross-sections provide clues to understand the nuclear structure and offers a good testing ground for ideas about nuclear forces. In addition, complete information in this field is very much required for application in accelerator-driven subcritical system.}

5 illus, 1 table, 44 ref

015495   Soma A K;Singh L;SINGH M K;Singh V;Wong H T (NO, Institute of Physics, Academia Sinica, Taipei 11529, Taiwan, Email: htwong@phys.sinica.edu.tw) : Neutrino and dark matter physics with sub-keV germanium detectors. Pramana J Phys 2014, 83(5), 829-38.

Germanium detectors with sub-keV sensitivities open a window to study neutrino physics to search for light weakly interacting massive particle (WIMP) dark matter. We summarize the recent results on spin-independent couplings of light WIMPs from the TEXONO experiment at the Kuo-Sheng Reactor Neutrino Laboratory. Highlights of the physics motivation, our R&D programme, as well as the status and plans are presented.

7 illus, 20 ref

015494   Shubhchintak;Neelam;Chatterjee R (Physics Dep, Indian Institute of Technology Roorkee, Roorkee-247 667, Email: rcfphfph@iitr.ac.in) : Capture cross-section and rate of the <. Pramana J Phys 2014, 83(4), 533-43.

Calculate the Coulomb dissociation of ^{15C on a Pb target at 68 MeV/u incident beam energy within the fully quantum mechanical distorted wave Born approximation formalism of breakup reactions. The capture cross-section and the subsequent rate of the 14C(n, γ)15C reaction are calculated from the photodisintegration of 15C, using the principle of detailed balance. Our theoretical model is free from the uncertainties associated with the multipole strength distributions of the projectile.}

5 illus, 33 ref

015493   Sangawar V S;Golchha M C (Polymer/Nanomaterials Research Laboratory, Govt Vidarbha Institute of Science and Humanities, Amravati, Maharashtra, Email: manisha_golchha22@yahoo.co.in) : Thermally stimulated discharge conductivity study of zinc oxide thermoelectrets. Indian J pure appl Phys 2014, 52(10), 704-7.

The dc electrical conductivity of ZnO nanoparticles and its thermoelectrets have been studied in the present paper. Thermal stability of ZnO nanoparticles has been investigated by DSC. The thermoelectrets were prepared by polarizing the sample by applying different polarizing fields (E_P) at constant polarizing temperature (T_P) for constant polarization time (t_p). The thermally stimulated discharge current (TSDC) studies have been made on ZnO sample at a constant heating rate in the temperature region 313-473 K. It has been observed that the conductivity of ZnO nanoparticles has been increased with increase in temperature and field. The thermograms are plotted between log σ and temperature (10^{3/T). The dependence of TSDC data on polarizing agents i.e. field and temperature is explained on the basis of theoretical predictions.}

3 illus, 1 table, 15 ref

015492   Sahoo S;Middya T R;Sit S K (Electronics & Instrumentation Engineering Dep, Dr. Meghnad Saha Institute of Technology, P.O. Debhog, Haldia, Pruba Medinipore-721 657, Email: swagatdebmsit@yahoo.co.in) : Dielectric relaxation of ethanol and N-methyl acetamide polar mixture in C₆H₆ at 9.90 ghz. Pramana J Phys 2014, 83(4), 579-95.

Debye relaxation times (τ_jk) and dipole moments (μ_jk) of binary (jk) polar mixtures of ethanol (EtOH) and N-methyl acetamide (NMA) dissolved in benzene(i) are studied by studying conductivity of solution at 9.90 GHz for different temperatures, different mole fractions (x_j) of ethanol and different weight fractions (τ_jk) of the mixtures, respectively. The variation of τ_jk-x_j from linear slope of imaginary (σ"_ijk) against real (σ'_ijk) part of total conductivity (σ*_ijk) curve reveals solute-solute (dimer) or solute-solvent (monomer) molecular associations up to x_j = 0.0-0.3 and thereafter, solute-solvent molecular associations. τ_jks from the ratio of slopes of σ"_ijk-ω_jk and σ'_ijk-ω_jk curves exhibit solute-solvent molecular association for all x_js which are consistent with the μ_jk-x_j curves at all temperatures except at 35°C. This signifies the validity of both the proposed methods in estimating τ and μ. The molecular dynamics of the polar mixture are ascertained from Eyring rate theory. Theoretical dipole moments from bond angles and bond moments (μ_theo) are also calculated to predict associational aspects.

9 illus, 3 tables, 18 ref

015491   Saadatmand D;Marjaneh A M;Heidari M (Physics Dep, Quchan Branch, Islamic Azad Univ, Quchan, Iran, Email: alimoradimarjaneh@gmail.com) : Dynamics of coupled field solitons: a collective coordinate approach. Pramana J Phys 2014, 83(4), 505-17.

In this paper author consider a class of systems of two coupled real scalar fields in bidimensional space-time, with the main motivation of studying classical stability of soliton solutions using collective coordinate approach. First, author present the class of systems of the collective coordinate equations which are derived using the presented method. After that, we follow the dynamics of the coupled fields with local inhomogeneity like a delta function potential wall as well as a delta function potential well. The results of the investigation of the two coupled fields are compared to each other and the differences are discussed. The method can predict most of the characters of the interaction.

6 illus, 25 ref

015490   Rani A;Singh Y P (Temperature and Humidity Standards, CSIR National Physical Laboratory, Dr K S Krishnan Marg, New Delhi-110 012, Email: ypsingh@nplindia.org) : Comparision of Transfer standard industrial lamps against PTB assigned radiance Temperature of vacuum and gas filled tungsten strip lamps. MAPAN 2013, 28(2), 129-40.

Accurate determination of temperature is one of the prime requirements in almost all the areas of physical metrology as it affects the process of any of the industrial manufacturing products. Planck's equation serves the best approximation for determining temperature of a thermal radiating source. The ratio of pyrometric output signal due to intensities of two radiating sources can be utilized to measure temperature of an unknown source in terms of the temperature of reference metal freezing point source or a high stability tungsten strip lamp. The present paper provides an assessment of a set of tungsten lamps having strip or ribbon filament when compared against the emission of high stability standard lamps. The temperature measured in terms of electrical current across the lamp terminals has been estimated with an uncertainty reasonably acceptable for accurate determination of radiance temperature by these lamps. The uncertainty of temperature at each comparison point for lamps under assessment has been evaluated and reported. The best uncertainty of temperature was estimated to be ±1.7 K at 1073 K, ±1.5 K at 1273 K and ±3.7 K at 2473 K. The uncertainty at 1,073 K is higher as compared to at 1,273 K, is because of very low value of photocurrent signal produced due to low intensity observed at this temperature. The industrial strip lamps, compared against reference standard lamps serve as accurate sources of radiance temperature for comparing the disappearing filament Opto-spectral pyrometers used as direct temperature measuring instruments in the laboratories and in industries in the range above 1,073 K to as high as 2,500 K.

9 illus, 9 tables, 31 ref

015489   Prommee P;Khateb F (Telecommunications Engineering Dep, Faculty of Engineering King Mongkut's Institute of Technolgy Ladkraban, Bangkok 10520, Thailand, Email: pipat@telecom.kmitl.ac.th) : High-performance current-controlled CDCCC and its applications. Indian J pure appl Phys 2014, 52(10), 708-16.

This paper presents a new high performance active element named Current Controlled Currents Differencing Current Copy Conveyer (CC-CDCCC). The main features of this element are large dynamic range, wide bandwidth and high accuracy. Furthermore, its intrinsic resistances of two input current terminals can be independently set by external balancing bias currents which lead to use low number of active elements. To demonstrate the high performance of the CC-CDCCC, two current-mode signal processing applications are presented in this paper i.e. universal filters and quadrature oscillator. Both of these applications are electronically controlled for a wide range of frequencies and they employ single CC-CDCCC and two grounded capacitors which are advantageous for monolithic integration. PSpice simulation results using the 0.25 μm CMOS technology from TSMC are included to verify the correct functionality of the proposed circuit.

17 illus, 2 tables, 27 ref

015488   Phillips D R (Physics and Astronomy Dep, Institute of Nuclear and Particle Physics,Ohio University, Athens, OH 45701, USA, Email: phillips@phy.ohiou.edu) : Describing one- and two-neutron halos in effective field theory. Pramana J Phys 2014, 83(5), 661-71.

In this paper, the recent work our group has undertaken on effective field theory (EFT) analyses of experimental data pertaining to one- and two-neutron halo nuclei is discussed. The cases of ^{19C and 8Li (one-neutron halos) and 22C (two-neutron halo) are considered. For 19C and 8Li electromagnetic processes, such as Coulomb dissociation and radiative capture are considered. In the 22C system the way in which the measured matter radius can be used to derive constraints on the two-neutron separation energy of this very neutron-rich system is shown. In each case the Halo EFT's ability to correlate different experimental observables with one another, in a modelindependent manner, and up to an accuracy that is determined by the separation of scales in the halo system is shown.}

5 illus, 1 table, 45 ref

015487   Palit R (NO, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai-400 005, Email: palit@tifr.res.in) : Recent results from digital INGA at BARC-TIFR Pelletron Linac Facility and future plans. Pramana J Phys 2014, 83(5), 719-28.

Experimental campaign aimed at studying various high spin phenomena using the Indian National Gamma Array (INGA) at the BARC-TIFR Pelletron Linac Facility has been successfully completed. The array consisting of a large number of Compton-suppressed clover detectors was coupled to a digital data acquisition system with 96 channels. The present system provides higher throughput, better energy resolution and better stability of gain for the multidetector Compton-suppressed clover array compared to its previous conventional system with analog shaping. Selected results from this array are discussed which highlight the exotic shapes, novel excitation modes and interesting isomers of the nuclei. The preliminary results from the experimental efforts to improve the sensitivity and capability of the array by adding ancillary detectors are also described briefly.

9 illus, 30 ref

015486   Nayak B K (Nuclear Physics Div, Bhabha Atomic Research Centre, , Mumbai-400 085, Email: bknayak@barc.gov.in) : Determination of neutron-induced fission cross-sections of unstable nuclei via surrogate reaction method. Pramana J Phys 2014, 83(5), 799-806.

Heavy ion reaction studies around Coulomb barrier energies have been generally used to investigate the effect of the structure of projectile/target on reaction dynamics. Other than providing an understanding of basic physics of the reaction dynamics, some of these reactions have been used as tools to serve as surrogates of neutron-induced compound nuclear fission cross-sections involving unstable targets. In this paper, we report some of the recent results on the determination of neutron-induced fission cross-sections of unstable actinides present in Th-U and U-Pu fuel cycles by surrogate reaction method by employing transfer-induced fission studies with ^{6,7Li beams.}

4 illus, 21 ref

015485   Nandan H;Bezares-Roder N M;Chandola H C (Physics Dep, Gurukula Kangri Vishwavidyalaya, Haridwar-294 404, Email: hnandan@iucaa.ernet.in) : Screening mechanism and multi-vortices in dual QCD vacuum. Indian J pure appl Phys 2014, 52(4), 271-6.

The screening effects in a chromodynamic vacuum which act as dual superconductor in the background of the magnetic condensation, have been studied. The colour charge and colour electric flux screening mechanism have been investigated and these screening effects are shown to be responsible for the colour confinement in dual QCD. It is also demonstrated that with the transition from the type-II to type-I in dual QCD vacuum at strong coupling constant as α_s ≈ 0.5, there exist n-vortex solutions with Bogomol'nyi-Prasad-Sommerfeld (BPS) conditions.

36 ref

015484   Musmade P;Ligade V (NO, , Pharmaceutical Dep, Quality Assurance, Email: virendra123sl@gmail.com) : Sun protection factor: science or advertising. Curr Sci 2014, 107(10), 1635-6.

15 ref

015483   Mukhopadhyay S;MA W C (Nuclear Physics Div, Bhabha Atomic Research Centre, , Mumbai-400 085, Email: somm@barc.gov.in) : Nuclear triaxiality in the A ~ 160-170 mass region: the story so far. Pramana J Phys 2014, 83(5), 729-37.

Research in nuclear triaxial deformation has revealed many exciting facts and figures over the last one and a half-decades. Although wobbling motion of nuclei was experimentally discovered at the beginning of the last decade, after almost 25 years of its prediction by Bohr and Mottelson, efforts are still being put to understand this rare nuclear phenomenon in greater detail. The concept of transverse wobbling is one such recent attempt which successfully explains the evolution of experimentally observed wobbling frequency with spin. The population of triaxial strongly deformed (TSD) bands in the A~160-170 region is favoured for which neutron number (N = 92 or 94) is a topic of current debate. Experimental efforts are being put following Bengtsson's calculations which indicate that the elevated yrast lines for N = 92 isotones favour TSD population. In A~170 mass region, the ambiguity over the real character of certain strongly deformed bands has recently been removed by extensive experimental and theoretical efforts, and the bands have now been firmly established as either enhanced deformed (ED) or superdeformed (SD).

5 illus, 21 ref

015482   Mohanty B (School of Physical Sciences, National Institute of Science Education and Research, Bhubaneswar-751 005, Email: bedanga@niser.ac.in) : Net-proton measurements at RHIC and the quantum chromodynamics phase diagram. Pramana J Phys 2014, 83(5), 705-12.

Two measurements related to the proton and antiproton production near midrapidity in √ ^{sNN = 7.7, 11.5, 19.6, 27, 39, 62.4 and 200 GeV Au+Au collisions using the STAR detector at the Relativistic Heavy Ion Collider (RHIC) are discussed. At intermediate impact parameters, the net-proton midrapidity dυ₁/dy, where υ₁ and y are directed flow and rapidity, respectively, shows non-monotonic variation as a function of beam energy. This non-monotonic variation is characterized by the presence of a minimum in dυ₁1/dy between √ sNN = 11.5 and 19.6 GeV and a change in the sign of dυ₁/dy twice between √ sNN = 7.7 and 39 GeV. At small impact parameters the product of the moments of net-proton distribution, kurtosis x variance (Kσ2) and skewness x standard deviation (Sσ) are observed to be significantly below the corresponding measurements at large impact parameter collisions for = 19.6 and 27 GeV. The Kσ2 and Sσ values at these beam energies deviate from the expectations from Poisson statistics and that from a hadron resonance gas model. Both these measurements have implications towards understanding the quantum chromodynamics (QCD) phase structures, the first-order phase transition and the critical point in the high baryonic chemical potential region of the phase diagram.}

3v illus, 27 ref

015481   Lahde T A;Epelbaum E;Krebs H;Lee D;Meibner U G;Rupak G (NO, Institute for Advanced Simulation, Institut fur Kernphysik, and Jlich, Forschungszentrum Jlich, D-52425 Jlich, Germany, Email: t.laehde@fz-juelich.de) : Hoyle state in nuclear lattice effective field theory. Pramana J Phys 2014, 83(5), 651-9.

Review the calculation of the Hoyle state of 12C in nuclear lattice effective field theory (NLEFT) and its anthropic implications in the nucleosynthesis of ^{12C and 16O in red giant stars. We also analyse the extension of NLEFT to the regime of medium-mass nuclei, with emphasis on the determination of the ground-state energies of the α nuclei 16O, 20Ne, 24Mg, and 28Si by Euclidean time projection. Finally, we discuss recent NLEFT results for the spectrum, electromagnetic properties, and α-cluster structure of 16O.}

5 tables, 33 ref

015480   Kushwaha A K (Physics Dep, K N Govt P G College Gyanpur, Bhadohi-221 304, Email: akkphys_bu@yahoo.com) : Phonon spectrum and thermal properties of mixed semiconducting compound ZnS_1-xSe_x. Indian J pure appl Phys 2014, 52(10), 684-8.

Phonon spectrum and thermal properties of mixed semiconducting compound ZnS_1-xSe_x have been calculated by using a proposed three-body shell model (TBSM). This model incorporates the effect of three-body and short-range repulsive forces including second nearest neighbours, in addition to long-range Coulombic interactions in the frame work of rigid-shell model with both the ions polarizable. Using the above proposed model, the phonon dispersion relations, phonon density of states and Debye characteristic temperature have been calculated and plotted for the compound ZnS_1-xSe_x. The comparison of the theoretical results with the available experimental has been made along high symmetry directions. An overall good agreement between theoretical and experimental results has been found.

4 illus, 16 ref

015479   Kshetri R;Bhattacharya P (Physics Dep, Sidho-Kanho-Birsha University, Ranchi Road, P.O. Sainik School, Purulia-723 104, Email: ritesh.kshetri@gmail.com) : Novel approach for modelling the cluster detector and the SPI spectrometer. Pramana J Phys 2014, 83(5), 817-27.

A probabilistic approach has been presented in six recent papers (R Kshetri, J. Instrum. 2012 7 P04008; ibid., P07006; ibid., P07008; ibid., P08015; ibid., P12007; Appl. Radiat. Isotopes 2013 75 30) for modelling a general composite detector. In this paper, a simplistic view has been presented on the application of our formalism to composite detectors consisting of hexagonal closely packed encapsulated HPGe detector modules.We have presented modified calculations for the peak-to-total (PT) and peak-to-background (PB) ratios of the cluster and spectrometer for integral satellite (SPI) for the first time considering up to four-fold events. Instead of using an empirical method or simulation, we present a novel approach for calculating the peak-to-total ratio of the SPI spectrometer for high γ energies. Our work can provide guidance for designing new composite detectors and for performing experimental studies with the SPI spectrometer for high-energy γ -rays.

3 illus, 3 tables, 9 ref