The world's largest atom smasher will likely be fired up again in October after scientists have carried out tests and put in place further safety measures to prevent a repeat of the faults that sidelined the $10 billion machine shortly after startup last year, the operator said on Saturday.

The Large Hadron Collider was meant to restart in late September, but that will probably be pushed back two to three weeks, a spokesman for the European Organization for Nuclear Research said.

"We're pretty confident about the dates," James Gillies told The Associated Press, adding that scientists believe they understand the error that happened last year and how to prevent it occurring again.

An electrical fault caused by a faulty splice in the wiring shut down the giant machine on Sept. 19, nine days after it was started up with great fanfare.

The 20-nation operator, known as CERN, expects repairs and additional safety systems to cost about 40 million Swiss francs ($37 million) over the course of several years, Gillies said.

Once it is running, scientists will use the machine to smash together protons from hydrogen atoms inside a 27-kilometer (17-mile) circular tunnel under the Swiss-French border near Geneva.

By recording what particles are produced by the collisions they hope to better understand the makeup of the universe and everything in it.