To prepare humanity’s most complex machine for its next round of awesome physics, it’s not simply a question of flicking the ‘on’ switch.
The Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) near Geneva, Switzerland, has begun its long restart process after being powered down in February 2013 for repairs and upgrades. The whole startup process isn’t expected to be complete until early 2015.
“The accelerator complex has to start months before the LHC is back online because it’s going to need some serious TLC (in the form of recommissioning, debugging and tuning) following the shutdown,” LHC operation head Mike Lamont told Symmetry Magazine.
The 27 kilometer particle accelerator ring that straddles the Franco-Swiss boarder is only one component of the LHC, however. Before charged particles even reach the LHC’s monstrous super-conducting electromagnets, they must first be created and accelerated via a ‘daisy chain’ of smaller particle accelerators, each one slowly ramping-up the particles’ energies so they can be pushed to record-breaking speeds by the LHC.
On Friday, LHC engineers switched on the first component of the daisy chain: the source. The source is responsible for generating a reservoir of protons — by stripping electrons from hydrogen atoms, leaving protons behind — that can then be injected into the successive particle accelerators.
This week, engineers will start to recommission the Linac2, the first particle accelerator that gives the “beam” of protons their first boost.
Next up will be the chain’s Proton Synchrotron Booster, an accelerator that has seen the most significant upgrades since shutdown and is instrumental in pushing LHC science to the next level.
“When we get the beam going around the booster, it will be a very important moment,” said Paul Collier, the head of the beams department. “Among other things, we are making a complete upgrade of its control system, which is the nervous system of the machine.”
An interesting thing about all these successive rings of accelerators is that it’s not just the LHC that depends on the proton source, many other physics experiments at CERN are eagerly awaiting the upgraded equipment to come online.
Since the LHC’s start of high energy collisions in 2009, the huge physics machine has rarely been out of the spotlight. On July 4, 2012, physicists announced the discovery of a “new boson” in LHC data and, the following year, that boson was confirmed to be the Higgs boson — the exchange particle that endows matter with mass. Of course, the Higgs boson discovery isn’t the only groundbreaking discovery by the LHC (that list is growing fast), but it was the LHC’s prime mission to hunt down that one particle, the last undiscovered component of physics’ bedrock Standard Model.
The discovery of the Higgs not only won boson theorists Peter Higgs and Francois Englert a Nobel Prize for Physics, it was a huge triumph for the multi-billion Euro experiment that is recreating the conditions of the Big Bang in an effort to peel back the most profound mysteries of our subatomic universe.
2015 will see even higher energies and bigger collisions inside the LHC’s four key experiments (ATLAS, CMS, LHCb and ALICE), so many more exciting discoveries await.
Source: Symmetry Magazine