Evening star., 1950-02-10
Conversion of Elements
Enters Abundant Age
New Methods Spur Output
Of Valuable Substances
By Thomas r. Henry

chemists ancient dream which became
a reality with the f1ssion of the uranium
atom and which represents the only
tangible benefit for mankind yet to
come from this momentous event, Is
entering new age of abundance
Development of new methods, results
OF which remain unpredictable, has re-
suited in production of scores of ele-
mentary substances which otherwise do
not exist on earth and some of which
may be of far-reaching Importance, the
Atomic Energy Commission reports.
Actually transmutation slightly pre-
dated atomic fission. It was first real
lied with the invention of the cyclotron
at the University of California. Except
IN few instances, however, the amount
1t was possible to produce was very
small. Now, in the Commissions great
uranium ovens production of relatively
large amounts of elemental materials
non-existent in nature is routine and
Two missing elements, promethium and
technlclum, which disappeared from the
earth at least two billion years ago, have
oeen remade by atomic fission.
Split Never Symmetrical.
When Uranium 235 atom is hit bv
SLOW neutron 1t splits in two. Each
OF the fragments is a distinct element.
usually form of one of the more com.
mon materials OF which creation is COM
poseS The split, however, is almost
never symmetrical. One fragment usu.
ally Is much larger than the other.
ABOUT two years ago physicists at the
commissions Los Alamos laboratory
discovered the phenomenon of "spalla-
ZION, at first looked on as a curiosity
ouC now becoming of prime importancs.
IL results when atomic nuclei of anv
sort are bombarded with elementary
PARTICLES with energies of about one mil
non electron volts which chin. instead
OF split, the atom All sizes of niece.
may be Clipped off. When a target Of
relatively pure material is bombarded IN
TINS fashion as many as a hundred
olHerent elements are found In tina
oeorls. Uranium. for example. has beer
FOUND to yield all the 90 elements found
IN nature in some form, usually not the
most abundant isotope. Several isotope.
nave been discovered in the debris
Whlcn are entirely new, several of which
promise to be of considerable value tn
medical research
UP to now transmutation has been q
matter of breaking down atoms. In ths
spaliatlon process, however, workers at
the University of California have found
elements three places higher in the
atomic table than the target being
bombarded.
Inc phenomenon remains unexplain-
eo One theory is that chip consist
ing OF three protons, essentially the
nucleus OF lithium atom, is knocked
on and Immediately picked UP by an
other atom in the target.
Ine splitting of uranium in the atom
ic bomb results from bombardment with
Slow neutrons Work now is in progress
with high energy, fast-neutron bonn
bardment which will split such refrac-
tory atoms as bismuth, lead and gold.
which are approximately in the center
OF the atomic table. Here, it is found,
the most common split is into two equal
parts. A great many new forms of
matter have resulted from these ex-
periments. From bismuth alone about
nifty isotopes have been obtained
no $50 Materials Obtained.
Altogether about $50 elementary ma
terials have been obtained, hitherto un-
known in nature. Nearly all of them
have too few neutrons In their nuclei
to remain stable and change into other
elements by emitting POSITIONS, the short
lived elementary particles which have
the same mass as electrons but each Of
which carries one positive, instead OF
negative, electric charge.
In the fast neutron smaShes 1t is be-
lieved that the splits occur much more
quickly than those brought about by
slow neutrons-in either case a. matter
Of fractions of millionthS of seconds.
Perhaps the most notable achievement
in transmutation has been the produce
tion of trans-uranic elements elements
with atoms heavier and more complex
than uranium, which heads the table Of
the elements found in nature. The first
OF these produced were neptunium and
plutonium, which were essential for the
atomic bomb. Still heavier and more
complex were americium and curium.
obtained in such minute quantities that
it has been difficult to determine any,
thing about them.
Some progress is reported, however.
with americium. tiny bits of which have
been produced in metallic form.
The sample now available has been
found to have three times the activity Of
radium, so far as alpha particle radia-
ton Is concerned. 1t also en1its the
superpowerful X-rays, known as gamma
rays, but these are not quite so pene-
trating as those from a radium sample.
Los Alamos chemists now are bonn
harding some americium with neutrons
to produce the next higher element,
curium in metallic form. The extremely
minute samples of this synthetic ele-
ment available up to now indicate that
it is far hotter stuff even than the amer
icium. 5