THE RADIOCHEMISTRY OF PLUTONIUM - Sciencemadness.org

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solution should not be used because of possible interference in the electrodeposition
step. The eluate in the tube then is evaporated to approximately 1 ml in an aluminum
heating block at 75°C.
Electrodeposition
The residue from the vaporation is neutralized with 8 ~ potassium
hydroxide using phenolphthalein as indicator. When the solution is neutral, 2 ml of
sodium hypochlorite and 5 ml of 2 N potassium hydroxide are added to the tube, and
—
the contents of the tube transferred to an electrodeposition cell with distilled water.
(The final concentration of the alkali is 1 ~.) The Pu is electrodeposited on 1/2 in.
polished stainless steel disks at 200 mA for 5 hr. The apparatus and techniques for
the electrodeposition of Pu are described by Schwendiman et al.*
Determination of Alpha Activity
The a activity on the stainless steel plates can be determined either by”
the NTA (Nuclear Track Alpha) emulsion method or by the standard electronic
counting method. The background of the NTA method is 0.007 dpm, with an accuracy
of 1.6 dpm. A method of choice for more rapid evaluation of results is the electronic
determination of the a activity by the phosphor-coated mylar method described by
*Xc
Hallden and Harley. The phosphor method uses a 1-in. photomultiplier tube and an
all-transistorized amplifier and counter system designed
Group of the Los Alamos Scientific Laboratory!s Physics
described by Grave son et al. *3
The background of this
adjusted to an optimum efficiency of 45 ~.. The precision
factory for 0.1 dpm.
by P-1 (the Electronics
Division), similar to that
system is 0.015 cpm when
of this counting is satis -
*L. C. Schwendiman, J. W. Healy, D. L. Reid, and G. E. Hanford, HW-22680
(1951).
**N. A. Hallden and J. H. Harley, Analy-t. Chem. ~, 1861 (1960).
*3 R. T. Grave son et al. , AEC New York Operations Office, Rpt. NYO 1523 (1950).
(TID ORE, Oak Ridge, Term, )
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