Radiations from Y90 Zr97 Pr142, and Pr143

Radiations from Y90 Zr97 Pr142, and Pr143

516 BARTOL RESEARCH FOUNDATION NOTES [J. F. 1. observations have been made over temperatures between 900” and 1300” C. The initial conductance is ...

145KB Sizes 2 Downloads 74 Views

516

BARTOL RESEARCH FOUNDATION

NOTES

[J. F. 1.

observations have been made over temperatures between 900” and 1300” C. The initial conductance is found to obey Ohm’s law; its temperature dependence is of the usual exponential form with an activation energy of 1.1 volt. Optica1 absorption measurements show an absorption maximum at 4000 A.U. Assuming a simple semi-conductor model this is tentatively ascribed to a donor band at 3.1 volts below the conduction band. The above activation energy yields a value of 2.2 volts which, in view of the Franck-Condon principle, may correspond to the same donor band. * Assisted by the U. S. Navy Bureau of Ships and by the U. S. Office of Ordnance Research. THE LEVEL SCHEME OF In”6 * J. VARMA**AND C. E. MANDEVILLE

The disintegration of the 2.3-day Cdn6 and its isomer, the 43-day Cdng, has been studied with thallium-activated sodium iodide counters, The levels of In”6 have anthracene counters, and coincidence methods. been shown to have excitation energies of 0.335 (Tt = 4.5 hr.), 0.595, 0.825, 0.858, 0.935, 1.30, and 1.42 Mev., the first four levels being excited in the decay of the 2.3-day period alone and the latter three in decay of the 43-day activity only. The gamma transitions from the 1.3-Mev. leve1 proceed directly to the ground state of In116while al1 the transitions from the 1.42-Mev. leve1 terminate at the 0.935-Mev. level. The gamma transitions from the 0.595, 0.825, and 0.858-Mev. levels lead to the metastable state at 0.335 Mev. About three per cent of the transitions from the 0.858-Mev. leve1 terminate at the 0.825-Mev. leve1 which in turn de-excites by way of a 0.230 Mev.-0.260 Mev. gamma ray cascade or by emission of a 0.490-Mev. quantum in the cross-over transition. The angular correlation function for the 0.485-Mev.-0.935 Mev.-cascade in the decay of the 43-day Cd116is found to be essentially isotropic. A leve1 scheme for In ‘lg has been established by these measurements. * Assisted by the Joint Program of the U. S. Office of Naval Research and the IJ. S. Atomic

Energy Commission. ** Research Fellow, Bartol; permanent address, Morena (M.B.), India; at present at the University of Glasgow, Scotland. RADIATIONS FROM Yw, Zr”, Prm, AND Pr143 * B. L. SAEAF w, J. VAEMA- AND C. E. MANDEVILLE

The radiations of the above listed radionuclides have been investigated with the aid of scintillation spectrometers employing crystals of NaI(T1). A pure sample of Ygo, obtained from Oak Ridge, was found to emit gamma rays in an amount of at most 10-6 photon per disintegration. Es7 was produced at Brookhaven by slow neutrons on isotopie ZrQs. The gamma rays of the 17-hr. ZrQ78+Nb975 MOQ~ are of energies 0.67, 0.75, and 1.6 Mev., the hardest quantum’ appearing in only two per cent of the disintegrations. A sample of praseodymium

Dec., ws4.3

BARTOLRESEARCHFOUNDATTON NOTES

517

oxide (99.98 per cent pure) was irradiated by neutrons to produce Pr1h2 which was found to decay with emission of a single gamma ray at 1.6 Mev. NO gamma rays were detected in the disintegration of Pr143. Any present were estimated to have an intensity of upper limit 10-6 photon per disintegration. * Assisted by the Joint Program of the U. S. Office of Naval Research and the U. S. Atomic Energy Commission. ** Research Fellow, Bartol; on leave of absente from Agra College, Agra, India. *** Research Fellow, Bartol; at present at the University of Glasgow, Scotland. r Previously reported at 1.42 Mev. by Mandeville, Shapiro, Mendenhall, Zucker, and Conklin, JOUR. FRANKLIN INST., 254, 381 (1952). ENERGY

LEVELS

OF Rh’03 FROM

THE DECAY

OF Pd’Oz AND Ru”8 *

BABULAL SARAF*

The decay schemes of Pdlo3 and Ru lo3have been studied with the use of two scintillation spectrometers in coincidence. It has been observed that the electron Capture activity of Pd103is accompanied by faint gamma radiation having the several quantum energies of 40, 6.5, 300, 365, and 495 kev with absolute intensities per disintegration of 1 X lO--3,4 X lO-$, 1.2 X 10-4, 6.6 X 10-4, and 1 X 10-4. The gamma rays of energy 65 and 300 kev were found to be in coincidence. The inner bremsstrahlung spectrum associated with the Capture transition leading to the 57-minute isomeric leve1 in Rhlo3 is of intensity smal1 in comparison with that of the above mentioned gamma rays. The fi-decay of Rulo is accompanied by gamma rays of energies 55,440,495, 555, and 610 kev with absolute intensities per disintegration of 1 X 10-2, 5 X 10-3, 0.90, 5 X 10-3, and 6 X 10-2. A @-spectrum of end point 110 f 10 kev is coincident with the 610-kev gamma ray. A leve1 scheme for Rh103with probable orbitals has been proposed. * Assisted by the Joint Program of the U. S. Office of Naval Research and the U. S. Atomic Energy Commission. ** Research Fellow, Bartol; on leave of absente from Agra College, India.