[en] A new approach for lithium drifting in silicon is described where the silicon devices under drift are held at constant temperature and bias at normal air ambient, and the drift process is terminated at the end of an estimated time depending upon the thickness of wafers. A 4-channel lithium drifting unit with electronically controlled oven has been constructed for this purpose. Full details of the fabrication procedure are given. A sizable number of Si(Li) detectors have been fabricated using this approach. The quality of the detectors is tested with ²⁴¹Am alphas and conversion electrons from ²⁰⁹Bi and ¹³⁷Cs sources. The detectors are regularly used for nuclear physics experiments at this Centre. (author)

[en] Ion-implanted phosphors were prepared by implanting Sb in CaS at 25 keV with concentration ranging from 0-05 to 0.2 per cent by weight. Samples of similar concentration were also prepared using the conventioal technique. The spectral response under UV excitation of both types of samples is compared. (author). 6 refs., 3 figs

[en] A model for N-N interaction proposed earlier by Bhasin and Gupta (1985), has been extended to incorporate the tensor component of the nuclear force. Based on the quark compound bag model (QCB), the nucleon-nucleon potential has a short range repulsive core which is non-local and has a characteristic energy dependence and is expressed in terms of the parameters relating to the six-quark compound bag. To account for the low energy properties, this repulsive core interaction is supplemented by a phenomenological non-local potential containing both central (S-wave) and tensor components and operates only outside the QCB. Using this model, the results are analysed and compared wi th the experimental data for the electromagnetic form factors of the deuteron, the D-st ate observables, such as the quadrupole moment, the D-state probability, and the D/S ratio along with the n-p scattering phase shifts up to about 400 MeV . (author). 23 refs., 7 figs., 2 tabs

[en] Energy migration and transfer from acriflavine to rhodamine B and malachite green in poly (methylmethacrylate) have been investigated using the decay function analysis. It is found that the influence of energy migration in energy transfer can be described quite convincingly by making use of the theories of Loring, Andersen and Fayer (LAF) and Huber. At high acceptor concentration direct donor-acceptor transfer occurs through Forster mechanism. (author). 17 refs., 5 figs

[en] Excitation functions for the production of ⁶⁸Ga, ⁶⁷Ga, ⁶⁶Ga, ⁶⁵Ga + ⁶⁵Zn and ⁶¹Cu from α-induced reactions in natural copper have been measured in the energy range ∼10-40 MeV using the stacked foil technique. A stack of nine copper foils was irradiated by a 40 MeV α-beam. The γ-rays emitted from the irradiated samples were recorded. Excitation functions have also been calculated theoretically using a statistical model with and without the inclusion of pre-equilibrium emission of particles. Pre-equilibrium component simulated by exciton model shows that the inclusion of pre-equilibrium emission gives better agreement between experimental and theoretical excitation functions. Pre-equilibrium fraction depends on the incident energy and the target mass number. (author). 26 refs., 15 figs., 3 tables

[en] The data on the θsub(lab)=7deg excitation functions of ¹²C(¹⁵N,⁴He)²³Na reaction between Esub(cm)=9.42 and 17.33 MeV for 28 states upto an excitation energy of 8.940 MeV in ²³Na have been subjected to statistical analysis. In addition to statistical fluctuations, the results of the analysis indicate the existence of non-statistical structures at Esub(cm)=10.66, 10.93, 10.38, 12.62, 13.16, 15.32 and 16.18 MeV. (author). 57 refs., 4 figs

[en] Excitation functions for the reaction ¹⁸¹Ta(α,xn)sup(185-x)Re, sup(107,109)Ag(α,ypxn) and ⁵⁹Co(α,ypxn) were obtained from measurements of residual activity of stacked foils from thresold to 60 MeV. The excitation functions for the production of ¹⁸¹Re, ¹⁸²Re, ¹⁸³Re, ¹⁸⁴Re, ¹⁰⁵Ag, ¹¹¹In, ⁵⁴Mn, ⁵⁶Co, ⁵⁸Co and ⁶⁰Co, are being presented. The experimental data are compared with calculations considering equilibrium as well as pre-equilibrium reactions according to the hybrid model of Blann. High energy part of the excitation functions is dominated by the pre-equilibrium reaction mechanism. Calculations were done using a priori calculational method of Overlaid Alice Code of Blann. Most of the excitation functions in the energy range mentioned above could be very well fitted with the hybrid model calculation for exciton number n=4 with nsub(p)=2 and nsub(n)=2. The overall agreement with theory is good. Certain discrepancies, however, indicate the necessity to revise the hybrid model with respect to emission of complex particles. (author). 33 refs., 13 figures

[en] Poincare gauge theory is derived from a linear theory by the method suggested by Gupta for deriving Einstein's general relativity from the linear theory of a spin-2 field. Nonlinearity is introduced by requiring that a set of tensor fields be coupled to the Noether currents of the Poincare group (energy-momentum and spin). (author)

[en] In addition to the Kerr-Newman metric with cosmological constant several other metrics are presented giving Kerr-Newman type solutions of Einstein-Maxwell field equations in the background of deSitter universe. The electromagnetic field in all the solutions is assumed to be source-free. A new metric of what may be termed as an electrovac rotating deSitter space-time- a space-time devoid of matter but containing source-free electromagnetic field and a null fluid with twisting rays-has been presented. In the absence of the electromagnetic field, these solutions reduce to those discussed by Vaidya (1984). 8 refs. (author)

[en] Some subtleties regarding regularizations in computing the soliton energy of degenerate systems are discussed. (author)