Scientists debunk 'Angels and Demons' antimatter

* Antimatter "bomb" in film not likely, physicists say

* Antimatter as energy source also a stretch

By Julie Steenhuysen

CHICAGO, May 19 (Reuters) - "Angels and Demons," the recently released film version of the Dan Brown thriller, focuses on a plot to destroy the Vatican using a small amount antimatter pilfered from the European particle physics laboratory CERN, the world's largest particle accelerator.

Some of the world's top particle physicists attempted to sort through facts and fiction about antimatter on Tuesday, and comment on their real quest behind CERN -- to unlock secrets about the origins of the universe.

"Antimatter atoms exist, but it is very difficult to make them," Rolf-Dieter Heuer, director-general of CERN, or the European Organization for Nuclear Research, said on Tuesday in a telephone briefing.

Antimatter particles are subatomic particles that are mirror images of matter, added Boris Kayser of the Fermi National Accelerator Laboratory in Batavia, Illinois, and chairman of the American Physical Society's Division on Particle Physics.

When the two come together, they annihilate one another, and their mass is released in the form of energy.

In Dan Brown's book, on which the Sony Pictures film was based, a quarter gram of antimatter was thought to be the equivalent of 5,000 tonnes of dynamite, enough to wipe out everything within a half mile (0.85 km) or so.