ACD in 2006 CERN beam test Here I am listing beam test ACD issues for discussion: ACD will be represented in CERN beam test instrument by minimum 4, and maximum 8 tiles upon their availability; single-row chassi with FREE board; and appropriate GASU cables Preliminary position of the tiles is shown in next slide. Priority in tile positioning is subject for the discussion. Tile 1 is placed on the top of the “tower” space adjacent to the beam, and represents the closest to the real backsplash case. I am concerned that the propagation of Monte Carlo proving over large range of angles may be not correct; 180 degrees with the tile in a plane normal to the beam direction (exact backsplash) is very important direction and has to be validated in a beam test ACD shall be mounted in the frame which allows flexibility of tile positioning depending on MC results. Tile mounting is done by taping tiles to the frame rather than using flight design of screwing them down

BEAM 1 2 6 BEAM Tracker tower 3 7 4 Tracker tower 5 8 Grid with calorimeter ACD tiles

Hardware availability: Positioning of the tiles outside of the container (Idea of L. Baldini) can be considered if it has significant mechanical advantages Hardware availability: Tile # Tile description Tile # per ACD Fiber Cable Status 1 Top tile, 33 cm by 33 cm, “flight spare” H-2 Spare 150 cm, needs PMT end parts Tile is ready, cable needs work. Will be ready by 3/31/06 2 Top tile, old design, 33 cm by 33 cm N/A Old design, 150 cm, needs PMT end parts Tile needs some re-furbishing, cable needs work. Ready by 3/31/06 3 Tile from QualUnit, 17 cm by 33 cm E-422 Does not need a cable; has both 50 cm long WLSF bundles Ready, will be available from SLAC 3/31/06 4 Tile from QualUnit, 17 cm by 33 cm. Will use only one fiber bundle if another one is too short O-320 Does not need cable; has 42 cm and 100 cm long WLSF bundles 5 O-124 6,7 10 cm by 10 cm tiles from GSFC external trigger setup Has 35 cm long WLSF bundle for single PMT Ready, available now 8 “E” tile, 17 cm by 33 cm, flight one, but had wrong dimensions that’s why was rejected E-01 Needs clear fiber cable, use spare 150 cm, needs PMT end parts

FREE board and chassi – will be borrowed from SLAC (ACD QualUnit) in the late March. Ready for use GASU cables – available, both from SLAC (ACD QualUnit) and from GSFC. Check the lengths - Alex Action items: Agree ACD tiles number and positioning – Philippe, Eduardo, Benoit, Ronaldo, Alex, all interested – by 01/15/2006 Agree ACD mechanical arrangement (concept) – INFN, Alex, Gary – by 01/25/2006. Include needed grid modification in the task for machine shop Approve the use of (doubled) flight spare tile “H” – Eduardo, Dave Thompson, Alex – by 12/31/2005*) Provide exact dimensions of ACD hardware – Alex, by 12/31/2005 Provide chassi mockup (if available) and tile (example) to INFN – Alex, 12/31/2005 Finish detailed ACD mechanical arrangement - INFN, Alex, by 02/28/2006 *). GSFC has 2 flight spare tiles “H” for 6 tiles of the same design in flight ACD. The idea is to use on of these spare tiles, leaving another one as a spare.