After eight years of banging subatomic particles together, CERN's Large Hadron Collider (LHC) is getting a major upgrade. In a ceremony on Friday, the high-energy physics laboratory broke ground on the High-Luminosity LHC (HL-LHC) project that, when it goes online in 2026, will increase the collision rates of the LHC by up to a factor of seven and allow around 10 times more data to be collected.

Though the LHC has been up and running since 2010, the new HL-LHC upgrades have been on the drawing board since November 2011. The project involves 29 institutes based in 13 countries and was formally approved by the CERN Council in June 2016, followed by prototyping of elements of the hardware that will go into modifying the 27-km (16.8 mi) collider ring.

CERN says that the new work will require replacing 1.2 km (3,937 ft) of the ring and swapping out various magnets, collimators, and radiofrequency cavities at the LHC's two main sites in France and Switzerland. This will mean erecting new buildings and the cutting of new shafts, caverns and underground galleries that will house new cryogenic equipment, electrical power supply systems, and new plants for cooling and ventilation. Though the LHC will remain online during the work, there will be two technical stop periods as well as annual maintenance work.

The purpose of the HL-LHC project is to increase the number of collisions as the ring accelerates protons to near the speed of light. As these protons circle in the opposite directions to one another, the collisions are powerful enough to reveal much about the basic structure of matter and the fundamental laws of nature.

Currently, the LHC can manage up to a billion billion proton collisions each second. When it is completed, the HL-LHC will increase this rate, or "luminosity", by five to seven times. CERN says that this will mean 10 times more data to be collected over a decade that will help scientists to better understand rare phenomena like the Higgs boson particle's creation, decay, and interactions with other subatomic particles.

The HL-LHC will do this by squeezing the particle beam in the accelerator by passing it through a new bank of 130 magnets that include 24 superconducting focusing quadrupoles and four superconducting dipoles. As these increase the rate of collisions, sixteen brand-new "crab cavities" will tilt the bundles of protons as they collide, making them appear to move sideways like a crab.

The laboratory says that the upgrades will also make the ring easier to maintain by making its components more accessible, while the power converters for the magnets will be relocated and refitted with superconducting cables to improve their efficiency.

"The High-Luminosity LHC will extend the LHC's reach beyond its initial mission, bringing new opportunities for discovery, measuring the properties of particles such as the Higgs boson with greater precision, and exploring the fundamental constituents of the universe ever more profoundly," says CERN Director General Fabiola Gianotti.

The video below discusses the upgrades.

Source: CERN

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