Installing collimators in the next long shut-down: plans, status and challenges

The first part of the collimation upgrade plan features the installation of 4 collimators in the 2 DS of point 3, in addition to the upgrade of the existing collimation system. What makes this upgrade so special is that for the first time collimators will be placed within the continuous cryostat of the LHC sectors. For this purpose, 16 main dipoles and 8 main quadrupoles will have to be disconnected and displaced by about 4.5 m, as well as the 2 electrical feedboxes (DFBAs) on either side of the DS, in order to create the space required for installing the additional collimators. The collimators themselves, although remaining of the warm type, feature a design substantially different from the others, mainly imposed by tight space constraints. These collimator modules will have to be complemented by a special bypass cryostat whose function is to preserve the continuity of the technical systems along the arcs (magnet powering, cryogenics and insulation vacuum), while providing cold to warm transitions to the beam tubes where the collimators are placed. The status of this collimation upgrade project is presented, with special emphasis on the collimation in the DS of point 3; design & integration studies in this point, as well as the status of the design and manufacturing of all the associated new equipment (DS collimators, Short Connection Cryostats, and new cryogenic extensions to the QRL) are outlined. An overall plan of the surface and tunnel preparation activities, in the perspective of a 2012 shut-down implementation, is discussed.