in favor of nitric acid.
Hydrochloric acid gas was then
passed for 15 - 29 minutes in an ice-cold solution of the
ahove sample and iron was removed by ether extraction.
The
iron-free solution was evaporated and dissolved in 8N HNO,.
The maiority of the samples were clear at this stage, but
when turbidity persisted, HF, HNOz process was repeated.
2 mi 5% NaNO, solution was added to the hot 8N HNO, solu-
tion of the sample and after cooling was passed thru 5 ml
Agix-8,
(190 - 200) mesh, NOz form anion exchange column.
After washing the column with 8N HNO, and Con-HCl respectively, Pu was eluted
from the column with a mixture of
75 ml Com-HCl + 1 ml HI.
The eluate, after repeated evapor-
ation with HNO, and HC], was passed thru another 2 ml
column of anion exchange resin and then plated on a
polished stainless steel disc at a current density of
1 amp /cmé,
The plutonium sample was deposited on 190 mm
area and counted*on an alpha-spectrometer system (the
spectrometer consisting of four diode detectors of 200 mm2
surface area).
The electronic system consisted of Tennelec
power supply (TC 908), a pre-amp (TC 164), a linear ampli-
fier (TC 211), hiased amplifier (TC 252), Nuclear Diode
discriminator (ND S31), Nuclear Diode router (NP 521) and
a Nuclear Data 512 channel analyzer (Series #139).
The
hackgrowund levels, hased on 3 - 6 day counts, were as
follows:
at 4.90 mev (Pu242) (a.AnS5 - 1.0034 cpm): at 5.15
mev (PuZ39*24My (mH - .9N34 cpm); at $.49 mev (Pu238) (N.000
-
20855928
.0905 cpm).
Resolution of the detectors was ahout 65 -