1. ECS workshop, CERN, may ‘00M. Ferro-Luzzi LHCb Vertex Detector System Reminder of current VELO design Controls: Motion mechanics Vacuum system Cooling system What needs to be done ?

2. ECS workshop, CERN, may ‘00M. Ferro-Luzzi Mechanics: current (obsolete) design Side flange Bending hinges Detector support and cooling Bellows (22000 signal wires) Support frame Si detector moves by 30 mm

3. ECS workshop, CERN, may ‘00M. Ferro-Luzzi VELO in Motion Function: detector halves movable vertically by 0-30 mm with (rough) intermediate steps (formerly, only “open/closed”). Provide remote controlled system to align the complete VELO in the x-y plane with respect to the beams, within the range  5 mm. Controls: stand alone use internal and external info (e.g. from VELO tracking, background monitor(s), from LHC BPMs, LHCb alignment survey ?) Interlock: Will involve several (delicate!) levels of safety (hardwired, PLC’s, …) Use beam alarm, background levels, position monitors, etc.

4. ECS workshop, CERN, may ‘00M. Ferro-Luzzi Differential Vacuum System LHC beam line vacuum TP Aluminium exit foil heat exchanger PE PI PE TP GV TP PI PE PI GV TP heat exchanger IOG LHC_north PI LHC IOG LHC GV LHC _ north PI LHC north IOG LHC_south PI LHC south GV PEPE PI PE TP GV TPTP GV LHC _ south GP 20 m beam pipe GV SP PI GV SP PI GV PE GV PEPI PE PI N2N2 Pressure reducing valve Restriction GV Over pressure safety P SP GV NEG Si detector vacuum bypass auxiliary bypass PI auxiliary bypass bypass

5. ECS workshop, CERN, may ‘00M. Ferro-Luzzi VELO Vacuum System Design: Si stations are in a separate vacuum (~10 -4 mbar) Separation from beamline vacuum (~10 -7 mbar) via thin Al foil self-opening valves Controls: stand alone use internal and external info (from LHC vacuum system) Interlock: Will involve several (delicate!) levels of safety (hardwired, PLC’s, …) exchange status info with LHC vacuum system, hall status, etc.

6. ECS workshop, CERN, may ‘00M. Ferro-Luzzi Cooling system with mixed-phase CO 2 *

7. ECS workshop, CERN, may ‘00M. Ferro-Luzzi cool to 20  C CO 2 gas-liquid storage tank 57.3 bar at 20  C CO 2 supply line compresssor P [W] flow restrictions supply line expansion valve cooling lines gas only pressure (temperature) regulating valve heat to 20  C Mixed-phase CO 2 Cooling system See LHCb 99-046/VELO

8. ECS workshop, CERN, may ‘00M. Ferro-Luzzi VELO Cooling System Design: provide a cooled pipe with sufficient cooling power for each Si module settable pipe temperature (-25 … 10 °C) self-adjusting flow of coolant by physical loop Controls: stand alone use internal and external info (from vacuum system, Si stations) Interlock: Will involve several levels of safety (hardwired, PLC’s, …) exchange status info with vacuum system, Si stations control, etc.

9. ECS workshop, CERN, may ‘00M. Ferro-Luzzi VELO Control Systems Tasks: Baseline design motion mechanicsunder way (re-design) vacuum systemdone (to be approved) cooling systemdone (to be approved) Define safety logic started motion mechanics beam controls/alarms, where/how are the beams dumped, … vacuum systemdifferential pressure, leaks, hardware failures,... cooling systemvacuum, Si status,... Design control systems started PLC-based  Jaap Kuijt, Luc Jansen Build and test control systems Control software, interfaces by whom ? LHCb ECS group ? How ? What ? LHCb and LHC interfaces