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Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC CSC detectors for T1 Brief description of the mechanics Some comments on the electronics System aspects January 17, 2003 Gas system and gas distribution Cooling HV … TOTEM plenary meeting -Marco Bozzo 1 Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Cathode electrodes panels Honeycomb panels 10 mm thick Nomex honeycomb 0.6 mm thick fiberglass skin (printed board) Cathode strips design same for both sides of detector Strips will cross at +/- 60 degree angle artwork obtained with printed board technique before gluing skin on panel Easy for board width up to 80-85 cm Only 1 company (CICOREL) for larger dimensions January 17, 2003 Final planarity within tolerances (+/- 0.2 mm) Easy to shape boards Two identical boards needed to build one detector TOTEM plenary meeting -Marco Bozzo 2 Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC CSC side A Wire support frame glued in position HV distribution and decoupling Printed board soldering pads Thickness defines anode cathode distance precise machining HV distribution to wires via decoupling resistor At amplifier end small board with decoupling capacitor, protection diodes and resistor Wires soldered in position, then glued Wire mechanical tension measured for each wire January 17, 2003 TOTEM plenary meeting -Marco Bozzo 3 Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC CSC Side B Fiberglass frame determines exact distance between cathode planes No HV slightly smaller dimensions Provides gas tightness Gas distribution in the two sides Gas distribution flow test with plexiglas detector and smoke gave uniform gas distribution in the gap Relative position of the two sides defined by 2 dowels January 17, 2003 TOTEM plenary meeting -Marco Bozzo 4 Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Gas distribution Hollow channel in the two sides Small holes uniformly distributed Test with smoke has proven good flow uniformity January 17, 2003 TOTEM plenary meeting -Marco Bozzo 5 Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Electronics 1 TOTEM telescope (5 planes) Is NOT equivalent to (from the point of view of R/O): 1 CMS chamber (6 planes) in TOTEM signals are generated far apart. CMS system foresees: sample and store with sophisticated analog memory to solve pile-up problems (SCA chip) and cope with trigger latency each cluster strip hit generates 16 data words (for 8 time samples) Fast trigger logic gives “digital” position of cluster with ½ strip precision (an order of magnitude worst than analog read/out) Coincidence of anode (wire) signals to determine timing of track January 17, 2003 TOTEM plenary meeting -Marco Bozzo 6 Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Read Out data channel count for present layout (halftelescope): 3135 anode wires with 3 mm pitch 5249 cathode strips of 5 mm pitch (both cathode planes are read out) Read out of full detector at each event creates too many data… need data reduction (track selection) at trigger level Work in progress on detailed definition of plane and telescope concentrator boards January 17, 2003 To reduce amount of data Maintain information like timing, pile-up etc. Understand which boards need to be redesigned/built TOTEM plenary meeting -Marco Bozzo 7 Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC GAS distribution Gas mixture prepared in surface (independent gas zone) Distribution Forward/backward in counting room Gas lines from counting room via the HF cable tray In T1 there will be 1 gas line for the 3 detectors in the half-plane (series flow) January 17, 2003 TOTEM plenary meeting -Marco Bozzo 8 Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Cooling All the power dissipated by the electronics inside the magnets must be “removed” using appropriate cooling. ~200W of power dissipated by the halfplane electronics (1kW for half-telelescope) For the number of channels considered at present Electronics boards installed on the support separator in which is integrated a water pipe for cooling. January 17, 2003 Tin~18-20 degrees Tout~25 degrees TOTEM plenary meeting -Marco Bozzo 9 Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC HV - Low Voltage Each CSC will have individual HV setting capability (on, off, current and volt. protect) Power must be adequate for largest rate foreseen (~ 30 μA/ channel) Low Voltage power regulation at plane level Power …. Total power needed(?) Use same system as CMS … (?) One rack on the platform on top of HF to house VME crate(s), gas distribution, Low and HV distribution. No transformers! Fringe field ~500 gauss. January 17, 2003 TOTEM plenary meeting -Marco Bozzo 10 Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Radiation All materials employed taken from the list of tested components for radiation. Generically (to be defined better) dose in T1 is approx two order of magnitude larger than in the CMS CSC. They can stand … 10 years at 1034 Our detector at most stand 1 year at 1033 January 17, 2003 TOTEM plenary meeting -Marco Bozzo 11
