European Laboratory for Particle Physics Cern-sl Division

Studies, taking into account the expected radiation doses for the different sections in the LHC accelerator tunnel, such as regular arcs and dispersion suppressors, show that electronic equipment can be considered for installation under the magnets. An estimate based on work carried out for String 2, the LHC Magnet String Program and extrapolated to the whole LHC machine gives a total of several thousands electronic crates to be housed under the magnets. This represents a substantial installation and a large expenditure. In order to qualify electronic equipment for installation in the LHC tunnel, from its radiation hardness point of view at the dose levels considered, an on-line radiation test facility has ben created and installed along a secondary beam line in the north experimental area of the SPS accelerator. The object of this paper is to present the type of electronic equipment and systems planned to be installed in the tunnel of the LHC and to give some preliminary results on radiation tests made for this electronics. Invited Paper presented at LHC Electronic Board Workshop Snowmass, Colorado, USA, 20-25 September 1999 Geneva, Switzerland November, 1999 ELECTRONIC COMPONENTS & SYSTEMS AND THEIR RADIATION QUALIFICATION FOR USE IN THE LHC MACHINE R. Rausch, CERN, Geneva, Switzerland (email: [email protected]) Abstract The two dispersion suppressor cells consist of fourThe two dispersion suppressor cells consist of four Studies, taking into account the expected radiation quadrupoles interleaved with four strings of two dipoles doses for the different sections in the LHC accelerator each. There is a total of 16 dispersion suppressors in LHC tunnel, such as regular arcs and dispersion suppressors, and their dipoles have the same length as in the arcs. show that electronic equipment can be considered for 2. SPACE FOR ELECTRONICS installation under the magnets [ 1,2,3,4]. An estimate based on work carried out for String 2, the LHC Magnet The LHC proton beams will circulate at 950 mm String Program [5], and extrapolated to the whole LHC above the floor of the tunnel. Taking into account the machine gives a total of several thousands electronic actual size of the dipoles, of the quadrupoles and of the crates to be housed under the magnets. This represents a tunnel floor construction tolerance a height of 380 mm substantial installation and a large expenditure. and a depth of 800 mm is available for electronic crates. Under each dipole and quadrupole space has to be left In order to qualify electronic equipment for installation in the LHC tunnel, from its radiation hardness point of view at the dose levels considered, an on-line radiation test facility has been created and installed along a secondary beam line in the north experimental area of the SPS accelerator. The object of this paper is to present the type of electronic equipment and systems planned to be installed in the tunnel of the LHC and to give some preliminary results on radiation tests made for this electronics. free for access to the supporting jacks and to allow access for the magnet transport system. A standard 6U crate with a 2U fan is accounted for a height of 350 mm, for a width of 600 mm with its support structure and for a depth of 800 mm including rear or front connections. Work, initially carried out for the String 2 [7] and extrapolated to the whole LHC machine, has shown that several thousands electronic crates, or equivalent assemblies, can be housed under the supra conducting magnets. Space has been allocated to the various data 1. THE REGULAR MACHINE LAYOUT acquisition and control systems, the beam instrumentation, the vacuum, the cryogenics, the corrector power The complete machine layout is described in the Large converters, the magnet protection equipment and to the Hadron Collider Conceptual Design document [6]. controls. For each of the eight arcs the current estimation For the purpose of this paper and in order to simplify of the needs is given in Tar the presentation, we will only consider the regular arc and Table 1: Estimation of the Number of Crates per Arc , the Dispersion Suppressors (DS) regions; we will not discuss the Long Straight Sections (LSS), in the middle of which are installed the experiments at the Interaction Systems Equipment Control Crates Crates