U.S. Alchemists Make Gold (Mar, 1948)
U.S. Alchemists Make Gold
Applying atomic magic to aid medicine and research, radiochemists duplicate nature’s elements and create new ones.
By Alden P. Armagnac
AT Oak Ridge, Tenn., the United States Atomic Energy Commission has gone into the business of manufacturing synthetic gold. The atomic pile is the Philosopher’s Stone, long sought by the ancient alchemists, which has the 24-carat touch.
Most curious part of the new enterprise is the odd behavior of the man-made gold. Though locked in the strongest vault, most of it would disappear within a week’s time.
Strange to say, this extraordinary way of acting actually enhances the gold’s value. What makes it so desirable is the fact that it is radioactive. Hence the ray-emitting “radio-gold” offers medical men a priceless tool for treating such maladies as leukemia, lymphoma and Hodgkin’s disease. At one institution alone, Vanderbilt University Medical School in Nashville, Tenn., it has benefited 61 patients in the first year of use.
For therapy and for “tagging” chemicals used in research, Oak Ridge’s alchemistsâ€”or “radiochemists,” as they call themselvesâ€” produce scores of artificially radioactive elements like radiogold. But they are by no means limited to “freak” products that have no counterpart in nature.
Just as easily, they can manufacture gold of normal behavior, perfectly acceptable to the U. S. Treasury! It may not be the best way to get rich quickâ€”the raw material, as for radiogold, is platinumâ€”but the fact that it has been done illustrates their prowess in transmuting the elements. If future generals and geologists worry no longer about strategic materials and dwindling natural resources because alchemists can make any wanted element from others, it will be hardly more fantastic than what has already been accomplished.
Behind the scientists’ amazing feats with cyclotrons and atomic piles lies a new understanding of the make-up of matter.
Chemists once believed that ninety-odd substances such as hydrogen and oxygen, called elements, were the ingredients of every material you could nameâ€”air, water, flesh, blood. All the atoms of each element, they thought, were just alike.
Varieties of Elements Discovered
Now the list of the world’s ingredients has been multiplied many times by the discovery that these elements have important varieties, called isotopes. More than 700 different isotopes are known today. Those of the same element give the same chemical reactions in a test tube, but they differ in weight and in more spectacular ways. You can safely handle any amount of uranium 238, one of the isotopes of uranium. Merely bring together something less than 220 pounds of another, uranium 235, and its spontaneous explosion will level a city. Some isotopes are stable. Others, even of normally well-behaved elements like iron and sulphur, may turn into something else while your back is turned!
Resembling a gigantic crossword puzzle, a remarkable “isotope chart” recently compiled by Prof. Emilio Segre, of the University of California, graphically illustrates the new idea of what things are made of. Rows and columns of squares form a pattern ascending diagonally from left to right. Horizontally, the chart ranges in order the 96 elements now known. Vertically, it shows all known isotopes of each element. Some squares even have double entries for “twin” isotopes having the same weight but different radioactive life. Counting these, the 720 filled-in squares have 785 entries in all. It looks pretty complicated, until you notice the beautifully simple relationship that the new chart reveals. Just two kinds of particles, it shows, make up every one of the 785 varieties and subvarieties of elements. One is the proton, the positively charged core of the hydrogen atom, discovered in 1886. The other is the neutron, an electrically neutral particle, discovered in 1932. These two particles are the true building blocks of the universe.
Join the right number of protons and neutrons to make the core or nucleus of an atomâ€”a neat trick if you can do itâ€”and you will have any isotope of any element you want. The number of protons determines what the element will be. One proton makes hydrogen, two make helium, and so on up to 96 for newly discovered curium. The total number of particles, protons plus neutrons, determines what isotope you will get. This is the number, therefore, that you write after the name of an element to identify a particular isotope. It’s all as simple as that.
To apply this idea and perform a bit of alchemy, you need only walk near an operating cyclotron with a little loose change in your pocket. For a while afterward, all your dimes and quarters will be radioactive enough to make a Geiger counter click. Subsequently, they’ll contain a trace of cadmium metal that the U. S. Mint never put there.
What has happened? An atom of silver in the coinâ€”say silver 107, which has 47 protons and 60 neutronsâ€”picks up another neutron from the cyclotron. The result is silver 108, the isotope that contains one more neutron than silver 107. It is radioactive and emits a negative electron, or beta ray. As it does so, one of its neutrons turns into a proton. It therefore becomes cadmium, the element that has one more proton than silver; and the isotope is cadmium 108, which is stable.
Wizards of Oak Ridge similarly produce “radioisotopes” (radioactive isotopes) of elements ranging from antimony to zirconium. Given time, they could change the world around pretty radically, since all their radioisotopes eventually turn into stable elementsâ€”and these are usually quite different from the elements they started with. Naturally radioactive elements can also be duplicated. Polonium 210, the natural form that turns into lead, has been produced from bismuth in a high-voltage atom gun at the University of Michigan.
Awe-inspiring to earlier chemists was their powerlessness to start, stop, or control in any way the radioactive process that in nature’s own good time gives birth to the various members of the radium, actinium, and thorium families. It could neither be hastened nor retarded by the most potent forces they could bring to bearâ€”the searing heat of the blast flame, the frigid cold of liquid air, or the crackling discharge of millions of volts of electricity. But now the great 184-inch cyclotron of the University of California has shown how to give nature a boost. It turns uranium directly into a remote member of the actinium family, Actinium Xâ€”a process for which nature requires five successive steps and, on the average, more than 700,000,000 years!
In 1939, a cyclotron yielded a radioactive metal new to scienceâ€”technitium, the first element to be discovered by its artificial creation. All newer elements, except francium, have come from the cyclotron and atomic pileâ€”astatine, neptunium, plutonium, curium, americium, and prometheum. Plutonium, of atom-bomb fame, was also the first synthetic element made by the pound.
Prometheum and technitium, the two synthetic elements believed most surely absent in nature, now are available from Oak Ridge. Substantial quantities could be produced as by-products of future atomic-power piles, if experimenters find they have important practical uses.
These men may well bear in mind the success story of the “Cinderella” element, columbium. As late as 1928, making a disk the size of a half dollar would nearly have exhausted the world’s supply of this steel-gray metal. In 1929, a Chicago chemist proudly exhibited the first rods and plates of columbiumâ€”and frankly admitted he couldn’t imagine any use for them. Today, as a result of wartime research, columbium has become indispensable. It forms a small but essential fraction of a heat-resisting alloy for the turbines of the world’s fastest jet planes. Any one of the newest elements made by alchemists may likewise prove a necessity in the world of tomorrow.