Inclusive and exclusive measurements in the projectile breakup of 7Li

The inclusive and exclusive measurements were carried out for ⁷Li projectile breakup on ²⁷Al target at 48 MeV. In the inclusive data we have observed a broad peak around the beam velocity for alphas and tritons. The exclusive data for alpha-triton coincidences show good agreement with the post-form DWBA theory of breakup reactions.     

Quasielastic reactions around the coulomb barrier in 16O+118Sn

Measurement of elastic and quasielastic reaction cross sections were done in ¹⁶O + ¹¹⁸Sn system at two different energies above the barrier. Attempts are being made to understand the results in the framework of coupled reaction channel model.     

Working group report: Collider and flavour physics

The activities of the working group took place under two broad subgroups: Collider Physics subgroup and Flavour Physics subgroup. Reports on some of the projects undertaken are included. Also, some of the leading discussions organized by the working group are summarized.      

Measurement of fission anisotropy for 16O+181Ta

Anisotropies in fission fragment angular distributions measured for the system ¹⁶O + ¹⁸¹Ta over a range of bombarding energies from 83 MeV to 120 MeV have been analysed. It is shown that statistical transition state model (TSM) with pre-scission neutron correction described adequately the measured anisotropy data. Strong friction parameter is found to be necessary to estimate the pre-saddle to pre-scission neutron ratio.     

Transition strengths and shapes of 2-qp bands in 74Se and 76Kr

The lifetimes of the states of −ve parity 2-qp bands of N=40 nuclei ⁷⁴Se and ⁷⁶Kr were measured. The transition strengths and quadrupole moments, obtained from the lifetimes, show a large collectivity of such bands in both the nuclei. The alignment frequencies were calculated from Woods-Saxon cranking model. Previously suggested quasi proton nature of band 5 and 6 of ⁷¹Se were argued to be based on quasi neutron excitations. The total Routhian surface calculations suggest triaxial shapes with large +ve and −ve values of triaxiality parameter γ after proton and neutron alignments in these bands respectively.     

Synthesis and characterization of electro-crystallized Cd-Sn-Se semiconductor films for application in non-aqueous photoelectrochemical solar cells

In the present investigation, thin films of CdSnSe have been developed on transparent conducting oxide (TCO) coated glasses by electrolytic deposition. The controlled incorporation of Sn in the semiconducting layer have been achieved by varying the concentration of Sn²⁺ from 5 to 22 g/l of SnCl₂ in the deposition bath. The semiconductor film grown on the glass substrate consisted of n-type CdSnSe semiconductor compounds (alloyed and/or mixed type) in the form of highly dispersed, spherically shaped polycrystallites as detected from X-ray diffraction (XRD) studies, atomic force microscopy (AFM) and scanning electron microscopy (SEM). Their optoelectronic properties were determined by spectroscopic analysis and electrochemical measurements. The performance characteristics of a photoelectrochemical (PEC) cell fabricated with the prepared photo-electrode and ferrocene-ferricenium redox couple in dimethyl formamide were observed under dark and illuminated conditions. The prepared semiconductor films were electrochemically characterized through capacitance-voltage measurements. The film that was obtained from 10 g/l of Sn²⁺ in the bath, showed an optimum spectral sensitivity and corresponded to a film thickness of 0.65 μm and stoichiometry of Cd:Sn:Se as 1:1:1. The pronounced PEC activity of this film compared to the others was attributed to the combined effect of space charge properties, electron-hole recombination processes and transfer of charges through the Helmholtz layer at the semiconductor-solution interface.     

Determination of thorium with organic reagents: uses of some aryl fatty acids

Phenylacetic-, phenylpropionic- and 1-naphthylacetic acids show definite promise as precipitating agents for the gravimetric determination of thorium. They can separate thorium from cerite earth and monazite sand, from solutions having thoria: rare earth oxide ratio up to 1 : 40, 1 : 16 and 1 : 14 respectively, by a double precipitation method. Foreign ions such as calcium, barium, strontium, titanium, zinc etc. do not interfere in the determination, of thorium by these reagents. As the thorium salts of these three acids are basic in nature, each possessing an entirely different composition, the determination of thorium by direct weighing of the precipitates is not possible and in each case the ignition of the precipitate to thoria is essential.     

Shift of millimeterwave window frequencies in relation to tropospheric radio meteorological parameters

In view of wide application areas of the millimeterwave frequency band (18–300 GHz) in recent years for various civil and defence applications including radar and communications, remote sensing and radio astronomy, we were prompted to undertake a theoretical estimate of the variation of specific attenuation (dB/Km) with radio meteorological parameters in clear weather conditions. The results of the estimation of the attenuation in this frequency band for some major locations in India from available radio meteorological data from NOAA, USA are presented in this paper. An appreciable amount of shift, which is mainly a function of the atmospheric pressure, temperature and relative humidity was noticeable in each of the window frequencies around 35, 94, 140 GHz and 220 GHz.