Harvard’s cyclotron is a relic.

The particle accelerator is so old, in fact, that the city considers it an historic building. And, now that Harvard wants to tear it down, the University needs the permission of the Cambridge Historical Commission before the wrecking balls can move in.

Built at the beginning of the Atomic Age, the cyclotron enabled scientists in the 1950s to look into the nuclei of atoms and learn more about the behavior of tiny particles. The machine was state-of-the-art when it was built but became obsolete within two decades.

Since then has been used for treating cancer patients. But with the advent of a new facility for cancer treatment in Boston, the cyclotron is no longer needed for medicine either.

And now Harvard has found a more important use for the Oxford St. site.

The University wants to demolish the cyclotron and build a 730-car underground parking garage next door.

Tonight the Historical Commission will hear Harvard’s case for doing away with the cyclotron, and in the coming months Harvard officials will meet with community groups to sell their development plans to wary neighbors.

In its day the cyclotron was called a “heavy cruiser” in cutting-edge physics research but now stands next in line for the bulldozer.

‘The Tool Chest’ of Physics

When Harvard’s cyclotron opened in 1949, the New York Times wrote that it was a state-of-the-art device that filled “a gap in the tool chest of physicists.”

Harvard had previously owned a cyclotron but that particular machine had been shipped to Los Alamos in 1943 and subsequently was used in research for the Manhattan Project.

The device that replaced it marked an advance for Harvard’s physics department. The new cyclotron could handle a higher voltage, making it one of the highest-capacity machines of its kind then in existence, says Higgins Professor of Physics Norman F. Ramsey, then an assistant professor who oversaw the cyclotron’s opening in 1949.

“This one was a very well designed cyclotron,” he says. “It’s very easy to run and operate.”

By the mid-1960s, the cyclotron was “a bit outmoded” for cutting-edge science research, says Mallinckrodt Professor of Physics Richard Wilson, who in 1999 invited physicists and top University administrators to a celebration of the cyclotron’s fiftieth anniversary.

But at the same time its scientific value had run out, scientists in an entirely different field were finding a new use for the machine.