Moving into the third dimension

One detail at a time, digital 3-D models of CERN’s various machines are being created by the Integration Section in the Machines & Experimental Facilities Group (EN/MEF) . The work, which requires painstaking attention to detail on a colossal scale, facilitates improvements to existing accelerators and the design of new machines in the future.


Virtual representation of the LHC

A complete digital mockup of the LHC in three dimensions already exists, including of course the tunnel, the machine systems including magnets and vacuum chambers, but also all of the various services such as cable ladders, piping systems and access control and so on. Only the colour and the texture of the surfaces betray that it is a mockup and not the real thing! The mockup of LINAC4 is finished too. The mockups for the SPS, ISOLDE and the entire PS complex, including transfer lines, are still being created. “Creating these 3-D mockups will allow us to work on forthcoming machine improvements, especially for the LHC. It will also be useful when the time comes to design new accelerators,” explains Yvon Muttoni, head of the section that is responsible for integration work on the accelerator chain, from LINAC4 to LHC.

Those improvements to the LHC are planned as early as next year. That means studies will have to be done, while the machine is still in operation, to establish the feasibility of integrating the new equipment. Yvon continues: "The 3-D mockups provide access to very detailed, realistic information, so that one can verify whether a new machine can be inserted. This makes it possible to organise the work and ensure that it is actually feasible, without having to await a technical stop so that we can get inside the tunnel to take measurements.”

The main challenge the team faces here is managing spaces and volumes, since there isn’t much room to spare in the tunnel. Every single item takes up a certain volume, of course; but in addition to that, you have to think about how much space will be needed for transportation and installation of equipment. “If you want to install a new piece of machinery in the accelerator, you have to check that there is enough space at the location where you want to put it and sufficient clearance between the existing components for the new item to be moved to and set up at that location.”

When a service starts making plans for modifying a machine, Yvon's team is alerted. Yvon describes the procedure: “We study how an improvement might be implemented by integrating it into the 3-D mockups. Once all of the affected services have validated the digitally generated image of the proposal, the actual modification can be carried out, during a technical stop." The Integration team has designed a special website that allows the experts in the various services to study the proposals to be validated. This validation process is meant to ensure that the 3-D mockup is technically sound and remains up to date. As Yvon explains, “The website has another function as a long-term data archive. It contains all of the documentation on the different machines— 3-D models, 2-D drawings, photographs, etc. In the case of some machines, the documentation had been lost. That is a shame, because it can be very useful as a source of inspiration for the design of future accelerators, particularly so as not to repeat past errors."

Currently, Yvon and his seven co-workers are working on a job that is planned to be done on the LHC in 2012. It involves a new type of collimator that will have to be inserted in the accelerator. “Some of the magnets will end up being displaced 4 metres in the longitudinal direction,” notes Yvon. “As a result, the jumpers (cryogenic junctions) will no longer be lined up! That means a new cryogenic link will have to be added, with a special shape designed to thread its way between the surrounding machinery. It’s the first, obvious task we have identified, as we are only at the start of the studies of the problem. But it’s likely that this displacement will give rise to more difficulties for other equipment. This is the kind of brain-teaser that we love to tackle!”




Watch the virtual tour of the LHC tunnel (3D images made in 2004) and the new LINAC4 (3D images made in 2008)

by Alizée Dauvergne