Science: Attack on the Atom

Last week Columbia University showed off its prize catch of the season: visiting Nobelman Enrico Fermi of Rome, who will conduct advanced courses in theoretical physics this winter. Before a room full of eager chemists at Manhattan’s Hotel Pennsylvania, bright-eyed, bubbling Professor Fermi made clear and simple sense of his prize-winning specialty: disintegration of atoms. He told the chemists how he releases enormous quantities of energy through neutron bombardment, how, like a modern alchemist, he transforms one element into another.

Neutron bombardment is so simple, said Professor Fermi, that “even theoretical physicists” (notorious for their aversion to laboratories) can do it. First step in shooting at an atom is to secure a plentiful supply of ammunition neutrons, tiny particles with mass but no electric charge. Professor Fermi gets his pocketful of bullets by placing a pinch of beryllium with some radioactive gas, radon, in a small glass tube, shaped like an electric light bulb. The active particles from the gas strike the beryllium, knock out some 20,000,000 neutrons a second. Next Physicist Fermi places the glass bulb, now full of neutrons, in contact with the element he wishes to bombard. He may, for instance, slip the bulb inside a finger-size cylinder of aluminum, leave it there for about an hour. Having no electric charge, the neutrons are immune to the negative electric fields surrounding the atoms, and the positive charges in the nuclei. So they leap unhindered into the hearts of the aluminum atoms, distend or crack them. When Professor Fermi removes the neutron tube, he inserts a Geiger-Miiller counter in its place, and the counter measures the exact amount of radioactivity (energy) produced.

Last step is chemical analysis of the new elements formed in the cylinder through”irritation” of aluminum atoms. These new elements are minute quantities of sodium and magnesium.

Although a terrific amount of Lilliputian energy is released in atomic disintegration (TIME, Feb. 6), there is, says Dr. Fermi, “no hope of a big explosion” at present. Still in the distant future is the old dream of cracking a cupful of atoms to drive locomotives, blow up the Western Front.