• M C Joshi

      Articles written in Proceedings – Section A

    • An electro-static beta-ray spectrometer, using a spherical condenser

      M C Joshi B V Thosar

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      An electrostatic beta-ray spectrometer using a spherical condenser has been constructed for study of weak sources, and its performance has been tested with accelerated electron beams. The device, which is intended for low energy range of electrons, has, for the slit system employed, the resolving power of 1·6% with transmission 1/44 of a sphere which compares favourably with that in other types of spectrometer. The electron energy E (in KeV) focussed is 4·37 times the voltage V. in K.V. on the electrodes.

    • Conveyor belt method for studying srort-lived activities: Ag108, Ag110 and In110

      M C Joshi B V Thosar

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      A technique for studying short-lived radio-activities is described. It is suitable for half-lives in the range from a second to several minutes. The activity is induced at one point in the sample spread over a moving, endless conveyor belt and is studied at another point. The equilibrium counting rate then depends on the speed of the belt. The activity of 22 sec. Ag110 and that of 2·3 min. Ag108 have been studied. The maximum energies of beta-ray groups were determined from absorption curves. Gamma-ray energies were obtained with a scintillation spectrometer. It is shown that in favourable cases, when two short-lived activities are present, the shorter-lived one can be filtered out by adjusting the speed of the belt.

      The authors believe that the technique can easily be adapted to an experiment where irradiation is obtained by means of a reactor and can be of great value when making detailed investigation of radiations from short-lived isotopes.

    • Decay of Samarium-153

      M C Joshi B N Subbarao B V Thosar

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      Radiations emitted in the decay of Samarium-153 have been studied in the Siegbahn-Slätisbeta-ray spectrometer. Using the internal conversion electron spectrum and the photo-electron spectrum with tin as radiator, the internal conversion coefficientak has been determined for 102 Kev. and 70 Kev.gamma-rays. The relative intensities of the threebeta-ray branches have been determined. A weakgamma-ray of energy 83 Kev. has been found and can be interpreted as a transition to the ground state from the first rotational level in Europium-153. The multipole order and character of the 102 Kev. transition is discussed.

    • Longitudinal polarisation of beta particles from Rb86, Pr144 and Co60

      M C Joshi V G Kulkarni C V Panat B V Thosar

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      An experimental set up is described for converting longitudinal polarisation of beta particles to transverse polarisation and for determining the degree of polarisation, using the method of Mott scattering from a thin gold foil. Electron polarisation in the energy range 90 to 150 KeV can be studied. The degree of polarisation for beta particles of energy 110 KeV from Co60, Pr144 and Rb86 has been determined and is seen to be equal to — V/C, within the limits of experimental error.

    • Decay of Eu155

      Kumari S Y Ambiye M C Joshi B V Thosar

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      Decay of Eu155 has been studied using intermediate imageβ-ray spectrometer, modified to makeβ-ē andβ-γ coincidence measurements. The followingβ-groups have been observed: 245 kev., 182 kev. and 145 kev. K/L ratio for 86 kev. transition is found to be ∼2·6. A decay scheme has been proposed.

    • Decay scheme of Eu156

      Kumari S Y Ambiye S D Bhagwat M C Joshi R P Sharma B N Subbarao

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      Decay of 15 days activity of Eu156 has been studied using intermediate image β-ray spectrometer and β-γ, β-ē and γ-γ coincidence techniques. The β-groups, β1 = 2450 Kev., β2 = 1180 Kev., β3= 720 Kev. and β4= 480 Kev. and the γ-rays (Kev.) at 89, 201, 630, 710, 810, 930, 1050, 1140, 1250, 1460, 2050 and 2180 have been identified. From coincidence studies, energy levels in Gd156 are proposed at (Kev.) 89, 290, 1140, 1360, 1540, 1840, 2050 and 2180.

    • β-γ Perturbed angular correlation in the decay of124Sb

      A P Agnihotry K G Prasad M C Joshi

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      The β perturbed angular correlation technique is applied to the determination ofg-factor of 603 keV (2+) state (τ = 8.5 psec) of124Te populated in the decay of124Sb. The activity was diffused into a thin iron foil. A small C type electromagnet was used for polarizing the sample. Internal field acting at the Tellurium nucleus in iron was used for perturbing the β-γ angular correlation. Theg-factor extracted isg = 0.28 ± 0.05. This is in good agreement with that obtained by γ-γ perturbed angular correlation method.

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