Geneva ? Scientists are preparing the world’s largest atom smasher to explore the depths of matter after successfully restarting the $10 billion machine following more than a year of repairs.

When the machine is fully operational, its magnets will control the beams of protons and send them in opposite directions through two parallel tubes the size of fire hoses.

In rooms as large as cathedrals 300 feet under the Swiss-French border, the magnets will force them into huge detectors to record the reactions.

One goal is to unravel the mysteries of the Big Bang that many scientists theorize marked the creation of the universe billions of years ago.

The restart of the Large Hadron Collider late Friday was hailed as a significant leap forward in efforts to launch new experiments — probably in January — on the makeup of matter and the universe.

The machine was heavily damaged by a simple electrical fault in September last year.

CERN decided Saturday to test all the protection equipment while there still is a very low intensity proton beam circulating in the collider. The tests will take 10 days, said James Gillies, spokesman for the European Organization for Nuclear Research, also known by its French acronym, CERN.

He said CERN decided against immediately testing the collider’s ability to speed up the beams to higher energy or to start with low-energy collisions that would help scientists calibrate their detection equipment.

In the meantime, CERN is using about 2,000 superconducting magnets — some of them 50 feet long — to improve control of the beams of billions of protons so they will remain tightly bunched and stay clear of sensitive equipment.

It is expected soon to be running with more energy than the world’s most powerful accelerator, the Tevatron at Fermilab near Chicago. It is supposed to keep ramping up to seven times the energy of Fermilab in coming years.

This will allow the collisions between protons to give insights into dark matter and what gives mass to other particles, and to show what matter was in the microseconds of rapid cooling after the Big Bang.

The Large Hadron Collider operates at nearly absolute zero temperature, colder than outer space, which allows the superconducting magnets to guide the protons most efficiently.