a flow rate of 0.4 ml/min.
The fractions were
counted for beta and
gamma activity.
The presence of europium-155, which was detected in the pH 2.8
fraction, was confirmed by two methods.
A beta mass absorption
curve was made using aluminum absorbers to determine the maximum
energy of the radionuclide, and a radiochemical analysis based on repeated cerium hydroxide and cerium fluoride precipitations was made
for rare earths.
This procedure was followed by analysis of the gam-
ma spectrum of the rare earth fraction.
Separation for Strontium-90
Duplicate samples of the original solution, each containing 0.95
gramsof dry soil, were analyzed for sr99 by the method of Kawabata
and Held.”
After reducing the amount of calcium in the sample by
treatment with 80 per cent HNO, the sample was dissolved in 0.2
N HCl and passed through a 0.5 cm? x 25-cm column of Dowex 50 of
100-200 mesh at a flow rate of 1-2 ml/min followed by a wash solution
of 0.2 N HCl.
Elution of certain of the cations was carried out with
0.5 per cent oxalic acid and 5 per cent ammonium citrate solution at
pH 3.5.
These eluates were discarded and the resin column which
now contained only Sr, Ba, and Ca was stored in the refrigerator for
two weeks to allow the y9° daughter of gr90 to build up. The y90 was
then reeluted from the column with ammonium citrate at pH 3.5 and