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Abstract  

The after effects of β -decay on time differential perturbed angular correlation (TDPAC) spectra of II–VI semiconductor CdS have been studied using β -emitting111Ag as well as111mCd as probe nuclei. The TDPAC spectrum of111Ag in CdS exhibits a time dependent interaction indicating that the preceding β -decay leaves the daughter nucleus in an excited state. The recovery time (τg) of the probe atom was found to be 16±6 ns while Abragam and Pound's relaxation time (τkr) was found to be 9±2 ns. The results show that β -decay does change the chemical environment around the probe atom.

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Summary  

Nuclear quadrupole interaction study using Time Differential Perturbed Angular Correlation technique has been carried out to identify the sites where hafnium can reside in hydroxyapatite in order to mimic the behavior of plutonium adsorption on hydroxyapatite. Hf(IV) has been found to occupy three sites with the quadrupole interaction frequency(ωQ) and its asymmetry(η): (i) ωQ = 136.7(5) Mrad/s, η = 0.54(1); (ii) ωQ = 300.1(9) Mrad/s, η = 0.35(2); (iii) ωQ = 124.6(5), η = 0.0(1). Narrow frequency distributions indicate the sites are well-defined. This study has been extended to barium orthophosphate to confirm our inference for the apatite structure.

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LetS be a 0-distributive semilattice and be its minimal spectrum. It is shown that is Hausdorff. The compactness of has been characterized in several ways. A representation theorem (like Stone's theorem for Boolean algebras) for disjunctive, 0-distributive semilattices is obtained.

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Abstract  

The concentration dependence of experimental diffusion coefficients of cobalt ions in presence of some alkali metal chlorides is examined in the light of the Onsager theory. The diffusion coefficients are measured in 1% agar gel using the zone-diffusion technique. The positive and negative deviations observed at higher and lower concentrations, respectively, are explained in terms of relative contributions of various types of effects occurring in the diffusion medium.

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Abstract  

The effect of some alkali metal chlorides on obstruction effect // and activation energy /E/ for the tracer-diffusion of cobalt ions is studied in agar gel medium using the zone-diffusion technique. It is observed that both the parameters, and E, decrease with increasing charge density of cation of the supporting electrolyte. This trend is explained on the basis of competitive hydration between ions and agar molecules and the relative distortion in the water structure brought about by these different ions and agar molecules, respectively.

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Abstract  

An alternative reaction route for the production of111In from rhodium target bombarded with a12C beam has been developed. Sulfate fusion was adapted for dissolution of the irradiated rhodium metal target. Indium was coprecipitated with La(OH)3 and purified by solvent extraction of the InBr3 complex into di-isopropyl ether and back extraction in 6M HCl. The chemical yield of the separation, determined using105Rh as tracer, was found to be above 90%. The radionuclidic purity of the separated111In satisfies the requirement prescribed for radiopharmaceutical preparations. The radioactivity yield achieved using this route was about 0.2 MBq/μAh.

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Abstract  

A new method for the possible incorporation of nuclear wastes has been attempted here by using ceramic matrix of TiO2 as a host precursor for confinement. Hafnium is used as a simulant for actinide high-level waste. After incorporating 181Hf tracer into TiO2 matrix, the leaching property of the resulting matrix was studied in water, sodium chloride and humic acid solutions. The leaching was measured in each of the case by following the radioactivity of 181Hf. TiO2 matrix has also been exposed to γ-radiation in order to simulate the radiation field for nuclear waste. It has been investigated with a nuclear technique called time differential perturbed Angular Correlation (TDPAC) that the lattice structure of titania remains undisturbed even under a strong radiation field. The leaching of 181Hf has also been studied after irradiating the TiO2 matrix with γ-radiation and the leaching behavior was observed not to change from that before irradiation.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: B. Shivashankar, H. Naik, S. Suryanarayana, P. Prajapati, V. Mulik, K. Jagadeesan, S. Thakare, A. Goswami, and S. Ganesan

Abstract  

The reaction cross-sections for 64Ni(n, γ) 65Ni at E n = 0.025 eV and 58Ni (n, p) 58Co at E n = 3.7 MeV have been experimentally determined using activation and off-line γ-ray spectrometric technique. The thermal neutron flux used is from the thermal Column of the reactor APSARA at BARC, Mumbai, whereas the neutron energy of 3.7 MeV is from the 7Li(p, n) reaction at Pelletron facility, TIFR, Mumbai. The 64Ni(n, γ) 65Ni and 58Ni(n, p) 58Co reactions cross-sections from present work are compared with the available literature data and found to be in good agreement. The 58Ni(n, p) 58Co reaction as a function of neutron energy is also calculated theoretically using TALYS computer code version 1.2 and found to be higher than the experimental data.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: Rita Crasta, H. Naik, S. Suryanarayana, P. Prajapati, K. Jagadisan, S. Thakare, S. Ganesh, V. Nimje, K. Mittal, and A. Goswami

Abstract  

The 100Mo(γ, n) reaction cross-section was experimentally determined at end point bremsstrahlung energy of 10 and 12.5 MeV using off-line γ-ray spectrometric technique. It was also found that 100Mo(γ, n) reaction cross-section increases sharply from the end point bremsstrahlung energy of 10 MeV to 12.5 MeV, which may be because of GDR around the energy region of 12–16 MeV. The 100Mo(γ, n) reaction cross-section as a function of photon energy was calculated theoretically using TALYS 1.2 computer code. The flux-weighted average values of 100Mo(γ, n) reaction cross-section for bremsstrahlung having end point energy of 10 and 12.5 MeV were also calculated using the experimental and theoretical data of mono-energetic photon. The present experimental 100Mo(γ, n) reaction cross-sections were compared with the bremsstrahlung flux-weighted average values of experimental and theoretical data and found to be in the lower side for 10 MeV and in the higher side for 12.5 MeV.

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