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High Luminosity, CERN, Geneva, Switzerland
Helping to Accelerate Success at CERN
And We’re Off!
It’s around 7 in the morning on Thursday, November 20, and the temperature is close to freezing. But the grey morning light and chilly air couldn’t dampen the high spirits of the dispatch team at Linde’s Schalchen plant. The excitement was palpable as they busied themselves preparing two refrigerator cold boxes for a “road trip”. The destination? CERN, the world’s largest particle physics laboratory saddling the Franco-Swiss border near Geneva. What is so special about this consignment you may be wondering? Well, on the one hand, this is no “ordinary” package. Each cold box weighs an impressive 64.6 tons, and is 26 meters long, 4.2 meters wide and 5.6 meters high. An oversized convoy of these proportions is a logistical masterpiece in its own right. It calls for ultra-precise planning of everything from transit permits and escort vehicles to the actual route. If the dimensions are out by even one centimeter, bridges, underpasses and tight junctions may become impassable. And that would jeopardize the delivery deadline. Which is a complete no-go for Linde Kryotechnik. The journey will take the cargo through Bavaria to the Passau-Schalding port, where the boxes will be shipped along the Rhein-Main-Donau canal. The last leg of the journey from Basel to Geneva will be completed by road.
Contributing to a Better Understanding of the Early Universe
What makes this transport feat truly fascinating, however, is the overarching mission. These two refrigerator cold boxes are about to join CERN’s High-Luminosity Large Hadron Collider (HiLumi) project. This groundbreaking project brings together thousands of scientists and engineers from around the world in a joint effort to push the boundaries of science. It will take the LHC into an entirely new performance regime, enabling exciting discoveries previously considered impossible.
The objective of HiLumi is to increase the current Large Hadron Collider (LHC) design luminosity by a factor of 10. Luminosity is a key performance indicator of any accelerator. It determines the number of collisions that occur in a given window of time. The higher the luminosity, the more data the scientists can gather from their experiments, allowing them to observe and study rare processes and mechanisms in greater detail. Concrete target applications include the Higgs boson field and particle. The new HiLumi will produce at least 15 million Higgs bosons per year – compared with around three million based on the LHC performance in 2017. This opens up all kinds of new research possibilities as scientists tackle the many unanswered questions associated with this mysterious particle and gain a better understanding of why particles have mass and how the universe formed. Other areas of interest include new physics phenomena such as dark matter candidates or new forces.
When the Cold Sets In
The leap in performance required for HiLumi to run at these new levels of intensity calls for cutting-edge hardware including new superconducting magnets, crab cavities and an upgraded – even more advanced – helium cryogenic system. Enter Linde Kryotechnik! The company has been tasked with supplying two new 14 kW refrigeration systems (4.5 K) and matching cold compressors (1.9 K) to maintain the superconducting magnets at ultra-low temperatures. Each of these systems consists of a refrigerator cold box, a cold compressor cold box and several warm compressor modules. One system will be installed at the LHC site in Meyrin, Switzerland, and one in Cessy, France.
One Step at a Time
A major milestone was recently achieved with the delivery and installation of the compressor modules at the start of October 2025. A 220-ton crane and hydraulic pulling systems carefully positioned the modules in place. This delivery of the two refrigerator cold boxes in December is the second milestone in this staged project spanning three delivery phases. These boxes will be installed at ground level. Phase three is scheduled for February 2026. This entails delivery of the cold compressor cold boxes. Once again, meticulous planning and logistical skill will be center stage. These cold compressor cold boxes must be lowered into an underground cavern via a 72-meter-deep shaft with limited clearance. Once installed, these three assemblies will collectively form the backbone of the new helium refrigeration system powering HiLumi. It is anticipated that HiLumi will be operational from mid-2030 onwards once the complex installation, piping, connection and testing works have been completed.
Enabling Cool Breakthroughs
The HiLumi project is just the latest installment in the long-standing, successful history of collaboration between Linde and CERN. Linde has been supporting CERN’s cutting-edge research projects with state-of-the-art cryogenic cooling systems since 1962 and will supply well over 50 percent of the cooling power for future experiments. The decision to entrust the HiLumi helium project to Linde bears further testimony to CERN’s deep trust in Linde’s technical excellence and commitment to advancing fundamental research. In the words of Bernd Lindenmayer, manager of the CERN-HL22 project at Linde Kryotechnik, “We are honored to build on CERN’s continued trust in our ability to support their helium cooling needs. And it goes without saying that we are truly excited to be part of such a groundbreaking project pushing fundamental science into a new era. A project of this scale presents its own challenges and this calls for excellence on all fronts – reaching from systems engineering right down to the last nut and bolt, and from painstaking planning all the way to faultless execution. And I am proud to be part of a team that brings all these skills together to serve such a prestigious customer.”