During the week of 5 December, CERN hosted a series of meetings at the ideaSquare to discuss integration between the LBNF far site conventional facilities and the massive cryostat that will house the first DUNE neutrino detector. Immediately following, the Fermilab cryogenics safety panels for the LBNF and SBN projects held extensive discussions with CERN engineers.
CERN engineers have evolved the cryostat warm-structure design in two significant ways. It now requires fewer bolted connections, making assembly less labor-intensive, and some components were redesigned to ensure efficient transport down the Sanford Laboratory Ross shaft. Extensive finite element analyses, assembly and installation studies, and testing plans are in progress; some are complete.
Logistics planning is also under the microscope: how to scale the already massive ProtoDUNE detectors to the DUNE detector modules that are about 20 times bigger? This represents one of the larger challenges (poor pun intended) in delivering the LBNF/DUNE initiative. Assembly of the cryogenics systems, cryostats, and detector modules will represent a scale of industrial construction that demands, for example, weight-handling equipment, many contractor trailers, literally acres of laydown space for shipping containers, and much more.
Another challenge: how to integrate and manage terabytes of engineering and design drawings and data for LBNF and DUNE, given that 2D and 3D renderings come out of at least three enterprise CAD systems? We made good progress understanding how to identify and manage so called “collisions” – two things trying to be in the same space.
During the second half of the week the Fermilab cryogenics safety panels for the LBNF and SBN projects got up-to-speed on the cryostat technologies being developed to support the SBN and DUNE programs. Panel members visited the partially constructed ProtoDUNE cryostats (“membrane” cryostats) and the first completed ICARUS cold vessel, which uses an extruded aluminum structure.
Representatives of GTT, the French company that developed the membrane cryostat technology, provided extensive engineering presentations. Discussions with GTT focused on how penetrations below the liquid level are designed and constructed, and how this has been handled in other vessels to date. Further discussions with CERN engineers focused on design codes, testing protocols, and other safety aspects.
The days were long, but the face-to-face meetings and site visit were very productive and far more effective that what could be accomplished in a phone call. Future visits to learn more as the cryostat design progresses may be in store.