Scientists are restarting the world's most powerful atom-smasher over coming days, the European Organisation for Nuclear Research (CERN) said Sunday, as they prepare a new campaign to explore the secrets of the universe.

The 3.9 billion euro (5.6 billion dollars) Large Hadron Collider (LHC) was shut down in December to ready it for collisions at unfathomed energy levels. It was run for a few weeks after being successfully revived from a 14 month breakdown.

The particle collider -- inside a 27-kilometre (16.8-mile) tunnel straddling the Franco-Swiss border near Geneva -- is aimed at understanding the origins of the universe by recreating the conditions that followed the Big Bang.

"We should be getting beams back in the LHC between Monday and Wednesday, with the first high energy collisions - so the real start of the research programme - coming two to four weeks later," CERN spokesman James Gillies told AFP.

"This is as scheduled when we switched off in December."

In the weeks before the technical shutdown, the collider achieved over a million particle collisions and accelerated proton beams to energy levels never reached before, according to CERN.

Collisions reached a world record energy level of 2.36 teraelectronvolts (TeV), already allowing scientists to gather data.

But CERN now wants to reach 7.0 TeV to try to recreate conditions close to the Big Bang, and run it at those levels for 18 to 24 months.

Subsequently the scientists aim to reach the LHC's design energy of 14 TeV, but only following another long technical shutdown in the second half of 2011.

Before the LHC experiment, no particle accelerator had exceeded 0.98 TeV. One TeV is the equivalent to the energy of motion achieved by a flying mosquito.

The winter standby was used to bolster the accelerator for the higher electric currents demanded by such enormous energy levels, and upgrade its cryogenic cooling system.

The LHC, a global effort, aims to resolve physics problems including "dark matter" and "dark energy", thought to account for 96 percent of the cosmos.

The scientists' Holy Grail is to find a theorised component called the Higgs Boson, commonly called the "God Particle", which would explain how particles acquire mass.

The experiment, the fruit of decades of experiments and research by physicists from around the world, has even attracted Hollywood in recent years with the fictional blockbuster "Angels and Demons".