Extension of Alpha- and Beta-Decay Systematics of ProtactiniumIsotopes
As part of the program for obtaining data to extend the scope of the systematics of alpha-radioactivity and to obtain more data pertaining to the energy surface in the heavy region of elements, they have made some pertinent new measurements on protactinium isotopes. The heaviest isotope of protactinium hitherto reported is that of mass 234 and hence it would be of interest to know the beta-emission properties of heavier isotopes in order to tie them in with the known radioactive data in this general region. Since low-energy deuteron bombardment of U{sup 238} might be expected to lead to Pa{sup 235} and Pa{sup 236} by (d,{alpha}n) and (d,{alpha}) reactions and proton bombardment to Pa{sup 235} by the (p,{alpha}) reaction, these irradiations were made in the 60-inch cyclotron at energies of 19 and 9.5 Mev, respectively. The protactinium was chemically separated following the bombardment of natural uranium by a procedure which involved a number of manganese dioxide cycles coupled with extractions of protactinium from aqueous into organic solvents. The manganese dioxide cycles consisted of precipitating this compound from the solution of uranium in nitric acid, followed by centrifugation, dissolution of the solid with hydroxylamine solution, dilution, and reprecipitation. The dissolved precipitate from the last cycle was acidified, salted with ammonium nitrate, and the protactinium extracted with diisopropyl ketone, several washings with salted solutions being made to insure good separation from fission products. The protactinium was then washed back into a low acidity aqueous solution and after acidification was extracted into a benzene solution of thenoyltrifluoroacetone which forms a complex ion with the protactinium. This solution was then evaporated to dryness on a platinum counting plate leaving a weightless deposit of protactinium.
- Research Organization:
- Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
- Sponsoring Organization:
- USAEC
- DOE Contract Number:
- AC02-05CH11231
- OSTI ID:
- 932811
- Report Number(s):
- UCRL--589; AECD-2812
- Country of Publication:
- United States
- Language:
- English
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