Don Landress, age 12, of Lilburn, Georgia, for his question:

How does a cyclotron work?

The Atomic Age began at the close of the last century with the discovery of natural radioactive substances. Radioactivity revealed fascinating and useful new information about the structure of the atom. Scientists saw how nature's atom smashing worked, but they needed a cyclotron to copy the trick.
The first cyclotron was made by an American genius named Ernest Oliver Lawrence, in 1930. You might imagine it as a giant round house with immense magnets powered by tremendous electrical energy. But Dr. Lawrence knew that nature's stupendous forces work on simple principles that can, as a rule, be scaled down to handle able dimensions. His first cyclotron could be held in his hand, and it looked for all the world like a squat little robot turtle. This tiny cyclotron could do the enormous job of smashing atoms, though it could smash only a very few. And the nuclear energy released by smashing even 100 tiny atoms is hardly worth mentioning.
The nucleus of the atom is a tight fist of assorted particles. When a particle is lost, the tight package is rearranged and some of its nuclear energy is released. In nature, the nuclei of radioactive atoms are unstable and particles break away of their own accord. The cyclotron is a man made device that chips or smashes particles from atomic nuclei. As in nature, the atomic nucleus is changed and in the process it releases nuclear energy. However, a cyclotron smashes atoms with a bombardment of high speed missiles.
The bullets aimed at the target are subatomic particles, such as electrons, protons and heavier ions. The target may be a small plate of metal. The cyclotron accelerates the bullets so that they are going fast enough to pierce an atomic nucleus in the target. The secret of the acceleration lies in the strange relationship between electricity and magnetism. The subatomic bullets are electrically charged particles that can be swerved by magnetic fields.
A cyclotron houses two semicircular electrodes, like the halves of a huge metal pie. The electrodes generate magnetic fields. High alternating current switches the magnetic forces back and forth between them. The subatomic missiles may be charged particles from a heated wire. They are beamed into this intense magnetic field. There they are tossed back and forth and swirled faster and faster. At maximum acceleration they sweep around the rim of the magnetic field. Here a small door aims a beam of the speeding bullets directly at the target.
Since most of an atom is empty and there are spaces between atoms, most of the bullets will pass on through the target. But some will strike atomic nuclei. This one may chip off a particle, that one may score a direct hit and smash a nucleus to fragments. Every strike changes a nucleus and its atom in some way, and this remaking of atoms releases a quantity of nuclear energy.
The energy of the atom smashing bullets is figured in EV, short for electron volts. The BEV is a super cyclotron capable of accelerating beams of bullets to billions of electron volts. It uses new processes, more power and it is much bigger than the early cyclotrons. But it serves the same purpose. Its magnetic fields accelerate subatomic particles. The bullets are beamed to strike atomic nuclei in a target, thereby changing atoms into different atoms. Cyclotrons have been used to discover and create new elements. One of these new elements is plutonium the radioactive element used to make the atomic bomb.