EZ EEREGAZILTEREDS
”
ra
ra
i
the other alkaline earths.(4)
With trsicr tethmioue, a high yield of
carrier strontium can be obtained,
Several ecsid treatments are required
and the actual number depends on the ameunt of calcium which was leached
from the soil,
Following the fumirg nitric acid separation, thorium,
lead and any contaminating fission preducts remaining are scavenged with
yttrium hydroxide, and radium and barium are removed by a barium chromate
precipitation.
The daughter yttrium is milked after equilibrium and beta counted
as a measure of the strontium-90 activity.
Absorption corrections are not
necessary since the weight of the precipitate can be rigidly controlled
at this point.
Twenty milligrams of yttrium carrier are added just prior
to milking and the standards are prepared in an identical manner.
The
step-wise analytical procedure is given in section 6.2 of the Appendix.
Colt
OGLTLE
Samples are mounted on piastic cises, covered with Mylar, and
the assembly secured with a plasti: rioz.
The sample is clamped into
position under one of three oneeinch Anton halogenefilled steel window
GeM tubes (# 1007 M) which are surrounded by a guard ring (46 "pencil
tubes" Anton# 315) in anticoinciderce, shielded with 3 inches of mercury
and beta counted for at least one hour,
FEackgrounds less than one count
per minute are obtained using this counting system. (3)
(i)
Modification of the method reported by Willard, NoHe, and Goodspeed,
Bo Wes
(5)
More recently,
res
Indus oe
ENE o
Chems
Ans?,
mang,
ah (1936),
NYO-h700 @ Manual of Stacti.: © tistives,
LeVine, HeDo, Charlton, Loe, Greviicr, “:t., Low Background Nuclear
Counting Equipment, HASL-650, liars. 25, 1)