Evening star., 1949-10-03
Atmosphere's Rorest Gas
Is Now Being Extracted
Helium 8 Proving of Exceptional
Value in Physical Research
Bv Thomas X. Henry

Value in Physical Research
By Thomas r. Henry
NEW HAVEN, October 3.-The rarest
constituent of the earth's atmosphere, which
makes up less than thousandth of a bill
lionth of the air We breathe, is being ex-
tracted in nearly pure form and in ap-
preciable quantities by Yale University ply
sicists.
This substance is the light gas helium
3. It is of exceptional value In physical
research. Even its existence was unknown
until about five years ago, when 1t appeared
in transmutations which occur in the great
atomic ovens Of the Atomic Energy Commis-
sion; and this has been the major source
ever since.
The commission has produced about 20
cubic centimeters year-and that is about
the limit-by bombarding the light element
lithium with neutrons and transmitting it
to ordinary helium and tritium. or triple
weight form Of the lightest Of the elements.
hydrogen. This Is radioactive and changes
automatically into helium by losing one
electron from its nucleus.
Once this production started it was found
there was minute amount of the newly
found isotope in nature. There are two
sources Of the ordinary and heavier form
of the element helium 4, which was first
discovered IN Tile sun dpout oo years dso
and since has become an important indus
trial product.
Oil Wells Are Sources.
One is from oil wells. The gas obtained
from this source contains less than ten
billionth of the lighter form. The other is
from the atmosphere whose helium content
is between a thousandth and a ten-thou-
sandth of l per cent. But one part in q
million of this Is helium 3. That is, atmos-
pheric helium contains at least 10 times as
much Of the rare gas as oil well helium.
This was unavailable before the recent
great expansion of the liquid air business.
The atmosphere now is being liquef1ed by
various industrial firms at the rate Of hun
dreds of tons day in order to get out Of
it the chief constituents, nitrogen and
oxygen, both of which have wide industrial
application.
The helium ordinarily in the atmosphere
can be separated chemically from this liquid
air. There of course, are only drops out
of gallons and these are mixtures OF both
the light and heavy forms of the sun gas.
DR.. c. T. Lane and his associates OF the
Yale faculty have developed the process
of separating the two by recent expert
mental development.
Helium changes from gas to liquid
at only four degrees above absolute zero.
When this liquid is cooled couple of de-
grees lower, it becomes super liquid" the
only one known, with several properties
which seem to border on the supernatural.
For example, 1t Is impossible to hold this
super-liquid in any vessel. It flows over the
walls. It becomes super conductor of heat,
about 1000 times better than any metal.
It has been found that there are two kinds
Of helium atoms. One will flow only from
IAn IN ANII %11r .Ivx frove 4~1I -
heat. The primary Yale discovery was
that all the heliun atoms, together with
very few of the ordinary helium atoms,
flow only from hot to cold. In this way
1t is possible to concentrate helium 3 ap-
proximately rs per cent pure. The product
then can be further purified.
Small Amount Distilled.
Thus far three to four cubic centimeters
have been produced by this curious distilla-
tion method. Physicists of the University Of
Leyden In Holland, however, are setting up
apparatus to follow out the Yale method
and plan to go into mass production''-
that is, as much as one cubic centimeter
week This will be about four times more
than can be produced by the transmutation
method Of the Atomic Energy Commission.
The amount of tritium that can be produced
is very small. This exploding hydrogen"
has a half life Of about four years. Which
means that. starting with a milligram Of
tritium. it would require four years to get
out half milligram Of the light helium.
The light helium Is needed in many ex-
periments on the fundamental properties
of matter. It is doubtful whether it ever
will have much industrial application. Pres
ent indications are that it never becomes
q super-duid When temperature is reduced
from 218 degrees above absolute zero
strange transition to this super fluid form
takes place which now is believed to take
In all the ordinary helium. The liquid light
helium. however, appears to remain an
ordinary fluid up to the point of absolute
zero itself. There is reason to believe that
it never will become solid.
Among the features being studied is the
properties of solution of both the super
fluid and the ordinary fluid. Liquid helium
3 is the only thing that can be mixed with
liquid helium and remain liquid. Liquid
air, for example, would change at once into
Jumps of ice.
Questions and Answers