UNCLASSIFIED
—
sroospheric Storage of Strontium
:
me atwosphere has been sseapled at various altitudes to estimate
-resently stored in suspended forn,
Sr 90
’
Methods of Sampling
1$ cubic
Lower atmosphere (200 fect) — Samples were collected at a
Teet
per
e
an MSA Comfo filter which has an
Flow of
efficiency
of over 90% at 0.3 micron. The samples were collected on the roof bf the
frou
yew York Operations Office. Samples have been collected continuo
se
=
Q00 feet)
—- The region of the tropopaupe has
} equipped with cellulose filters. Duplioe
a
been 8
cate samples are collected at 2 flow of approximately 6000 cubic f
per
ainute.
The efficiency of collection of the filter paper appears
the range 90-95% (Appendix B ).
Stra
to design
Four flights have been completed.
tb be in
re (40 ~ 100,000 feet)— It was necessary for the] Laboratory
spec
or sampling in this region of
ateosphere from which dust had not previously been collected.
the
Although many devices are available for dust sampling in the lower
psphere,
the problems presented in the sampling at 100,000 feet aske these dbvices
entirely unsuitable. Preliminary calculations based on the best estimates of
expected concentration of activity set the requirement of volums ofjeir to be
' sampled at approximately 1000 cubic meters. Mince the only practich)
means of
attaining this altitude is by means of non-extensible helius filledi balloons,
consideration of weight of tie sampler and its self-contained powerl supply
vere of great import. These factors in sddition to the great reduciion in
air pressure end temperature at this altitude prompted the investightion of
electrostatic precipitation for the solution of this probles.
The most inviting feature of the electrostatic
Pabsage of air through the device without
pitator is the
free
ction allowing the freateat
air moving efficiency. At these altitudes, the ease of producing c#rona ioniss-
wae Without the use of excessively high voltages greatly reduces
Feaents in the charging device.
power re-
Prelininary testa in an evacuated bell jar demonstrated the feasibility of
: Aining contolled corona discharge restricted to a small region
afound the
talents Wire at this pressure by using a quasi-constant current powsr supply.
the
tions indicated reasonable dimensions would efficiently precipitate
dusts of interest.
rcure Ll iliustrates the basic features of the device.
It cons
ef four
ions ot © O.D. by 1/16* wall aluminas tubing each 13" long.
first
seetion
aichrs Ontains an insert §" long reducing the inner diameter to 2]785".
me wire .012" in diamster is supported qn an insulator and funs centrally
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