Large-scale particle-smashing can begin again, with the Large Hadron Collider (LHC) firing up after a two year downtime.

The LHC and its findings remain some of the most exciting scientific and technical achievements of the current age, abd it has now been upgraded for double the collision capacity.

The immense machine – buried in a 27 kilometre ring-shaped tunnel under the Franco-Swiss border - can now be fired at a mind-bending14 trillion electronvolts.

As part of the upgrade, engineers at the European Organisation for Nuclear Research (CERN) introduced two new proton beams – which are fired to create the LHC’s sup-atomic smashes.

“Today at 10.42am a proton beam was back in the 27 kilometre ring, followed at 12.27 pm by a second beam rotating in the opposite direction,” a statement from CERN said.

“After two years of intense maintenance and several months of preparation for restart, the Large Hadron Collider, the most powerful particle accelerator in the world, is back in operation.”

The first new experiments will be conducted at an energy level of 13 trillion electronvolts (TeV) around June this year, with the full-strength firing at 14 TeV on the horizon.

After being used in recent years to prove the existence of the Higgs Boson particle – which confers mass to matter – the LHC’s new level of atom-smashing will be used to investigate currently conceptual elements of physics such as antimatter and dark matter. .