Fission product yield studies in the reaction of 73,4 and 84.2 MeV12C with209Bi have been carried out using gamma-ray spectrometry. The cross sections for the production of fission products have been
determined. The yield distribution of fission products is found to be symmetric and broad with FWHM around 25 mass units and
peak near mass 107.7 and 107.0. The average number of neutrons emitted per fission have been found to be around 5.5 at 73.4
MeV and 7.1 at 84.2 MeV, respectively.
Present status of work on charge and mass distribution in medium energy fission of compound nuclei produced using various target projectile combinations is reviewed. Systematics of charge distribution parameters and their dependence on excitation energy of the fissioning nucleus is presented. Variation of mass distribution with excitation energy and mass and charge of the fissioning nucleus is discussed. Qualitative explanation of the data has been sought in terms of existing theories of fission. The importance of charge and mass distribution studies in identifying the different reaction mechanisms in heavy ion induced reaction is highlighted.
Authors:S. Lahiri, D. Nayak, A. Ramaswami, and S. Manohar
Heavy ion activation of natural terbium foil with 75 MeV 12C6+ results in the formation of carrier-free lutetium isotopes, 165–167Lu, and their corresponding decay products, 165–167Yb and 165–167Tm, in the matrix. Carrier-free lutetium and ytterbium isotopes have been separated quantitatively from terbium bulk target matrix using HDEHP liquid cation exchanger. Radiochemically pure thulium radionuclides have been obtained after the decay of ytterbium radionuclides.
Authors:R. Sampatkumar, A. Ramaswami, P. Kalsi, R. Singh, and S. Manohar
A simple technique based on the measurement of the ratio of alpha-decay constant to neutron induced fission cross section
for pure actinides using solid state nuclear track detectors (SSNTDs) is developed for the identification of the actinides
in trace levels in pure solutions. The alpha-decay constant to fission cross section ratios for depleted U,238Pu and240Pu have been measured for the epicadmium neutron induced fission of these actinides. The measured values are (6.19±0.34)·106, (6.95±0.26)·1012, (2.12±0.95)·109 and (2.18±1.58)·1011 sec−1·cm−2, respectively. These ratios can be used for the trace level identification of pure actinides.
Authors:A. Nair, A. Reddy, R. Acharya, P. Burte, and S. Manohar
A chemical neutron activation analysis method to determine trace amounts of palladium present in the uranium ores has been
developed. Palladium was concentrated on an anionic exchanger to purify from large amounts of uranium, iron and copper that
were present in the ore. The resin in which Pd was adsorbed was neutron irradiated and the activation product109Pd was assayed through its daughter109mAg by low energy photon spectrometry to estimate palladium. Both the 88 keV gamma-line and the 22 keV X-ray line (arising
out of the internal transition of109mAg) were used to arrive at the concentration values by a standard comparison technique. A thin window Si(Li) detector and
an HPGe detector were used for the radioactive assay. Detection limits and the advantage of using the X-ray line of Ag over
that of the gamma-line were discussed. An absolute detection limit of 0.12·10−9 g could be arrived at by the use of the 22.10 keV X-ray line in an interference-free condition.
Authors:Y. Scindia, A. Nair, A. Reddy, and S. Manohar
For the determination of phosphorus in different matrices, the derivative neutron activation analysis is especially applicable to aqueous samples, since the conventional neutron activation analysis is not useful for the determination of phosphorus. Phosphorus when reacted with ammonium molybdate 4 hydrate and ammonium metavanadate forms molybdo vanado phosphoric acid. This complex is preconcentrated by extracting into methyl isobutyl ketone. The organic phase containing the molybdo vanado phosphoric acid is neutron activated and the phosphorus is determined through the activation product of 52V. Preparation of this complex, its stoichiometry, application to trace level determination of phosphorus and improved detection limit are discussed. This method was applied for the analysis of industrial effluent samples.
Authors:P. Burte, A. Nair, S. Manohar, and Satya Prakash
The influence of chemical forms of iodine (I– and I2) on the uptake by wheat plant (Triticum aestivum) as a function of growth, in terms of days since germination, has been studied. The normalized amount on fresh weight basis of I– and I2 absorbed by root, shoot and plant as a whole was determined by independent experiments. Both chemical forms of iodine were tagged with131I for radiometric assay. The transport index, depletion factor and shoot to root ratios were determined. The total amount of iodine absorbed increases as a function of growth in case of both chemical forms; however, uptake and transportation of I– is greater as compared to I2.
Authors:H. Sodaye, P. Pujari, A. Goswami, and S. Manohar
This paper discusses the diffusion of Cs+ and Zn2+ ions through Nafion-117 cation exchange membrane using radiotracer technique. The validity of the Donnan's equation is checked for these ions using65Zn and137Cs radiotracers. The paper also discusses the diffusion of Cl– and I– anions studied by using36Cl and131I radiotracers. The probable mechanism of diffusion of these anions in the presence of Zn2+ cations is suggested.
Authors:R. Acharya, P. Burte, A. Nair, A. Reddy, and S. Manohar
Multielement analysis was carried out in two samples of natural rubies obtained from Kenya and Tanzania and a synthetic ruby obtained locally. The trace element profile was used to characterise the ruby samples. Instrumental Neutron Activation Analysis (INAA) by the single comparator (K0 method) was used to determine the concentrations of 22 elements with gold as the comparator. High resolution -ray spectrometry was employed for radiometric assay of the activation products. The accuracy and precision were evaluated by analysing standard reference materials such as USGS-W-1 and AGV-1 and were found to be satisfactory.