Description: 8 7 6 2 ; 7 4 7 6 : 7 8 : : ; half life of 3.781 plus or minus 0.010 years based on calorimetric measuiements. The calorimetric assay of the sample will be continued ior several years to decrease the probable error. The decay scheme for /sup 209/Po--/sup 209/Po/ isitopic mixtures is being determined. The gamma spectrum is being studied using two sources of different isotopic composition. Definite peaks were established at 76, 260, 300, 575, and 9l0 kev. Various multiple coincidence experiments indicated that the 300- and 575-kev photons and the 76-kev x-ray are in triple coincidence. Relative intensities of the various gamma rays from the two different sources indicated that the 575-kev photon is associated with /sup 208/ Po decay, while the 260- and 910-kev states are attributed to /sup 209/Po. A theoretical estimate of the partial alpha half life for /sup 208/Po decay to the 2+ level in /sup 204/Pb (at 0.899 Mev) was made. This value (2.5 x 10/sup 6/ years) was determined graphically by extrapolation to an alpha particle energy of 4.2l1 Mev. /sup 209/Po--/sup 2o9/Po sources are being prepared for the investigation of the internal conversion electron spectra of these isotopes. Ion exchange techniques are being studied for the separation of /sup 227/Ac from / sup 227/Th, /sup 223/R a, and /sup 226/Ra. Naturally occurring lanthanum, thorium, and barium are being used as experimental substitutes. Composite elution curves indicated that lanthanum and /sup 232/Th can be successfully isolated with 2 M HCl, 3 M HNO/sub 3/, and ammonium acetate as elutrients. A purified form of the original Dowex 50W-X8 column packing matenial was used; the new material (AG-50W-X8) reduced tailing on the elution curves. /sup 228/Th was tentatively assigned a half life of 1.9132 years with an internal probable error of ...
Date: July 30, 1963
Creator: Eichelberger, J.F.; Grove, G.R. & Jones, L.V.
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Partner: UNT Libraries Government Documents Department