I'm dreaming of a white clean room...

New HIE-ISOLDE cryomodules are now under construction in a state-of-the-art clean room facility in SM18.


The HIE-ISOLDE clean rooms in SM18.

HIE-ISOLDE is set to be the world's leading nuclear physics site, ultimately accelerating radioactive nuclei to an impressive 10 MeV/u. Helping the facility reach this energy are new superconducting cryomodules, the first quarter-wave cavity module to be assembled at CERN and necessitating a custom clean-room in SM18.

At a towering five metres tall, the new clean room houses a custom assembly frame and associated equipment, moving the components of the 6 tonne cryomodules both vertically and horizontally while they are being assembled. "Each cryomodule is made up of some 10,000 parts, which have come from across the continents to be assembled here," says CERN TE engineer Lloyd Williams, who is managing quality assurance for the project. "Each part is checked by the CERN team, catalogued and thoroughly cleaned, before being installed in the cryomodule with sub-millimetre precision."

Not all clean room equipment is super high tech! This "tea strainer" is used to hold small elements to be cleaned, thus reducing contamination from gloves.

While piecing together this complex puzzle is tough enough, the team also needs to keep the module pristine during every phase of assembly. "The cryomodules feature a single vacuum, with no separation between the beam and insulation vacuums," says CERN TE engineer Yann Leclercq, who is leading the cryomodule assembly team. "This means the entire assembly zone needs to be kept as pristine as possible, as a single speck of dust could later pollute sensitive RF cavities and seriously affect the cavity performances. Our clean room has a constant flow of filtered air, keeping the construction area spotless, and we keep interventions in the room to a minimum to avoid any unnecessary contamination."

It's a delicate process, and one that will take the assembly team six long months to get just right with the help and support from the Beams and Engineering Departments. The first cryomodule should be completed and assembled in the HIE-ISOLDE facility by mid-2015. Then it will be given to BE-RF experts, the equipment owners, for final RF validation.

by Katarina Anthony