Particle Accelerator Robot: CERN's TIM and Where ABB Fits

Particle accelerators are hard places for people to work. The tunnels run for kilometres, and radiation, strong magnetic fields and the risk of oxygen deficiency limit when anyone can go in. A particle accelerator robot takes over some of those trips. This post follows the job from technicians in CERN's tunnels and the first robots that handled radioactive targets at ISOLDE, to the TIM monorail robots in the Large Hadron Collider and a Fermilab cobot that aligned an accelerator part on its own this year, and asks where ABB's cleanroom robots and GoFa cobots could fit.

A worker walks through a newly built HL-LHC tunnel at CERN, May 2025. Photo: Mmma98 / Wikimedia Commons (CC BY-SA 4.0)

How CERN started moving people out of radiation zones

CERN's accelerators sit in more than 50 km of underground areas holding thousands of pieces of equipment, according to a 2017 paper by CERN engineers. The biggest tunnel was built between 1983 and 1988 for the Large Electron-Positron collider, a 27 km ring about 100 metres underground that ran from 1989 to 2000 before the Large Hadron Collider reused it. People can only work in a tunnel like this during planned technical stops and long shutdowns, and the same paper lists intervention windows of under an hour over distances of kilometres.

The empty LHC tunnel with a transport vehicle during CERN's 50th anniversary open day in 2004. Photo: Juhanson / Wikimedia Commons (CC BY-SA 3.0)

Robots took over target handling at ISOLDE, CERN's radioactive ion beam facility. ISOLDE fires 1.4 GeV protons from the Proton Synchrotron Booster into targets to make exotic isotopes, and the used targets carry high levels of radiation. After the facility moved to the booster, with the first experiment on 26 June 1992, two industrial robots were installed in May 1995 to handle targets and ion source units without human intervention. During the long shutdown of 2013 they were replaced with more modern robots.

Industrial robots that once handled highly radioactive targets at ISOLDE, photographed in 2002. Photo: Maximilien Brice, CERN / Wikimedia Commons (CC BY 4.0)

CERN then built robots of its own. The LHC tunnel got the Train Inspection Monorail, or TIM, a battery-powered train that runs on a monorail fixed to the ceiling all the way round at up to 6 km/h. A 2017 paper by Mario Di Castro and colleagues lists its missions: visual inspection, radiation surveys, photogrammetry of the tunnel structure, fire detection and measurements on collimators and magnets. The wagons are only 30 by 30 cm so they fit through the sector doors, and TIM parks in a bypass while the beam runs. For indoor jobs CERN uses CERNBot, a modular platform for delicate interventions in the presence of ionising radiation.

TIM, the Train Inspection Monorail, on its ceiling rail in the LHC tunnel. Photo: M. Di Castro et al., CERN, ICALEPCS 2017 paper THPHA061 (CC BY 3.0)

Robots in the HL-LHC shutdown and Fermilab's cleanroom

The LHC is now in its third long shutdown. Since 7 September CERN teams have been dismantling sections around the ATLAS and CMS experiments to remove 28 superconducting magnets, including inner triplets installed between 2005 and 2007. The replacements for the High-Luminosity LHC use niobium-tin coils that reach 11.3 tesla, about 40 percent stronger, and the first new quadrupole is due in the tunnel at the start of 2029. CERN's knowledge transfer group counts 135 robotic interventions since 2015 and more than 112 mSv of radiation dose saved for personnel up to the end of 2018.

The LHC machine running through tunnel sector 3-4, photographed in 2009. Photo: Maximilien Brice, CERN / Wikimedia Commons (CC BY-SA 3.0)

Fermilab has the newest example, from cleanroom assembly. On 22 October the lab described how its PIP-II project, a 215-metre superconducting linear accelerator, uses a cobot to fit couplers onto spoke resonator cavities. Technicians tried aligning the heavy couplers by hand on prototypes in 2016 and 2017, and the job needs submillimetre, subdegree precision across 16 bolt holes while the cavity is open to contamination. The team bought its first cobot arm in December 2023, added a camera, and in July 2026 the cobot aligned a coupler autonomously. "We want to bring the technicians as far away from the cavity as possible while the cavity is open," said senior engineer Mattia Parise.

A niobium nine-cell superconducting radio frequency cavity at Fermilab. Photo: Z22 / Wikimedia Commons (CC BY-SA 4.0)

No ABB robot appears in these projects, and we found no public example of one in an accelerator, so ABB's role is a possibility. The Fermilab task looks like the work ABB's cleanroom robots are built for. ABB says they are certified to ISO 14644-1, and the IRB 1100 and IRB 1300 come in ISO 4 cleanroom versions with sealed bodies that keep grease, oil and particles off the product. For work beside technicians, the GoFa cobot can share its workspace with people without fences, and ABB's Ultra Accuracy option claims path accuracy down to 0.03 mm. Cells like these are usually laid out and tested first in RobotStudio.

An ABB IRB 1300 cleanroom robot handling trays inside a production cell. Photo: ABB

Where accelerator robots go after the HL-LHC

Some of the next robots are meant for places where people cannot work comfortably at all. On 17 October Bioengineer.org reported a study in Frontiers in Robotics and AI by the University of Rome Tor Vergata, CERN and the University of Arizona, in which a helium blimp mapped the stray magnetic field in the ALICE detector cavern, 52 metres below Saint-Genis-Pouilly. The airship is built from non-ferromagnetic PLA and Depron foam, so the field cannot pull it towards the magnet. Radioactive targets already get robot handling at CERN-MEDICIS, next to ISOLDE, where a KUKA robot moves irradiated targets that make isotopes for medical research. By the end of 2020 MEDICIS had supplied 41 batches of radioisotopes to nine hospitals and research facilities.

A KUKA robot handles an irradiated target at CERN-MEDICIS, 2017. Photo: Maximilien Brice, CERN / Wikimedia Commons (CC BY 4.0)

In factories, the closest match is Fermilab's cleanroom work. The team wrote its cobot code from scratch and says it could be tailored to other cleanroom processes such as the nanofabrication of microchips. Its cobots already cut some two to three hour cleaning and parts swapping steps to about an hour, and the team is working to shrink a 30-minute swap to as little as 5 seconds. ABB's GoFa, which ABB sells for machine tending, assembly and screwdriving, could suit that kind of job, though we found no published example of one in an accelerator lab. Our post on radiopharmaceutical production covers a related hot cell job.

An ABB GoFa cobot with a gripper and camera at a lab bench. Photo: ABB

Radiation and magnetic fields remain the hardest limits. TIM parks in a bypass while the LHC runs, out of reach of radiation and magnetic disturbance, and the ALICE blimp avoids ferromagnetic parts because fringe fields can upset electronics and actuators. People are the other limit. The 2017 CERN paper notes that maintenance robots in hazardous areas have needed skilled, dedicated shift operators, which is costly and slow because the interfaces on industrial robots are not intuitive. ABB says its GoFa and SWIFTI cobots are designed so customers need not rely on in-house programming specialists, and Fermilab kept its operator outside the cleanroom before handing the alignment to a camera.

Moving a GoFa arm by hand, the way a position is taught without writing code. Photo: ABB

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