University physicists pumped 99.999999 percent of the air out of their cyclotron in a vacuum test last week, and then announced that the machine would be finished some time next term.

The vacuum--ton one-billionths of an atmosphere--is one of the highest ever made in a a large container. Oil diffusion pumps produced it in the cyclotron's main chamber.

It is in this chamber that protrous are sent spinning at whirlwind velocities before they crash into fissionable material. However, all the air must be removed so that the protons will not collide with stray atoms in their path. This is the reason for the vacuum.

Absolute Zero

Although the chamber is 50 cubic feet in volume, the physicists have drained out so much air that the molecules left could easily be put on the head of a pin. Most of the instruments already register a pressure of absolute zero.

With the vacuum equipment out of the way, the main job now is building and attaching the oscillator to the cyclotron. As the protons spin around, the oscillator boosts their speed each time they pass. These successive boosts often result in velocities greater than 10,000 miles per second.

Magnets Already In

Since magnets were installed last spring, the machine can already duplicate such levitation feats as those that newsmen saw recently at the dedication of Columbia's cyclotron. But Harvard's physicists are waiting until the machine is finished before showing these stunts.

When completed next year, the cyclotron will be one of the four biggest in the world. Scientists will direct the machine's work toward the interactions of protons, neutrons, electrons, and other fundamental particles.