1. VELO workshop, Amsterdam, april ‘00M.Ferro-Luzzi Difficulties with current mechanical design recent FEA results: to obtain sufficient stiffness of center frame, a rather complex structure needs to be used  reduced space and accessibility MAFIA: WF suppressors on sides of the two detector boxes are needed  not easy to find a solution with current design because center frame is “in the way” and because of the fact that the two boxes are mounted separately into the tank Dynamic vacuum: we must have the option to insert a Titanium evaporator  not easy with current design must enter from the front of tank and, again, center frame is “in the way”  we propose a new design

2. VELO workshop, Amsterdam, april ‘00M.Ferro-Luzzi

3. VELO workshop, Amsterdam, april ‘00M.Ferro-Luzzi Plus points: center frame much stiffer optimally positioned short legs, no more problems of bending not any longer “in our way” (more accessibility to critical items of VD, see below) all “referencing” is achieved with a much simpler design alignment and reproducibility VD easier to mount and position in the tank build in complete VD at once solves accessibility problem on one side of the beam pipe no more need of tilting mechanism during VD installation easier access to the critical WF suppressor more accessibility for connection to exit foil possibility to install WF suppressors along detector box sides required for position “open” !! much space left on one side of the tank secondary vacuum pumps and, if required, a titanium evaporator with much more favorable design conditions (comes from side, instead of from front of tank) pumping on the detector boxes is more efficient New tank & frame design: summary

4. VELO workshop, Amsterdam, april ‘00M.Ferro-Luzzi Minus points: re-do FEA calculations two detector boxes are not interchangeable any longer (but individual stations can be) all feedthroughs on the same big flange all cables and repeater cards on same side present choice of feedthrough limits total number of pins to about 25000 !! New tank & frame design: summary (continued) Conclusion We like the new design.

5. VELO workshop, Amsterdam, april ‘00M.Ferro-Luzzi Cabling in vacuum: provide FEE cabling from feedthroughs to some available connectors coming from the hybrids cabling for cooling system and control (see definition below) cabling for temperature control of stations we assume some group will take care of testing the complete electrical chain Alignment: provide reference points for station alignment with respect to center frame provide reference points for external alignment of boxes guarantee internal alignment and reproducibility of boxes provide possibility to move the center frame via a remote- controllable XY-table interactive alignment with respect to beams using tracking, beam feedback control and XY-table internal alignment and reproducibility of detector stations we assume some group will take care of the complete LHCb alignment surveying NIKHEF VD responsibilities: how do we currently see it ? “YES, ours” “NO, not ours” (not included here: Pile-up and FEE)

6. VELO workshop, Amsterdam, april ‘00M.Ferro-Luzzi Cooling system and temperature control: provide a complete cooling system: “heat exchanger” (pipes) with sufficient cooling power at a fixed and stable temperature control and monitor of this cooling system (hardware and software) cooling, temperature control and monitor of the stations (though, we wish to be involved in this) VD vacuum (tank and detector boxes): provide important part of the vacuum system (chambers, flanges, feedthroughs), but we assume we do not have to provide the exit foil (CERN) we see the pumps, gauges, quadrupole mass analyzers, and LHC/VD interface valves as part of the infrastructure control and monitor of VD vacuum system (hardware and software). Note: this has to be integrated with LHC control system! NIKHEF VD responsibilities: how do we currently see it ? (continued) “YES, ours” “NO, not ours”

7. VELO workshop, Amsterdam, april ‘00M.Ferro-Luzzi End April: fix foil geometry and thickness End June: formal approval by LHC of VD design (LEMIC?) Early May: formal approval by LHCb/VELO of VD design Early May: formal approval by LHCb/VELO of VD design Mid May: formal approval by LHCb of VD design manufacture and test self- opening valves † design a Ti evaporator † build and test cooling system † manufacture and test self- opening valves † design a Ti evaporator † build and test cooling system † start producing manufacturing drawings build control and monitoring systems etc. start producing manufacturing drawings build control and monitoring systems etc. End December: draft TDR † = strong impact on LEMIC (my personal impression) Timeline and Milestones (highlights) manufacture prototype Al box, then leak & pressure tests † manufacture a WF suppressor model, perform RF studies † manufacture prototype Al box, then leak & pressure tests † manufacture a WF suppressor model, perform RF studies † build and test Ti evaporator complete testing (vacuum, RF, motion mechanics, cooling, etc.) build and test Ti evaporator complete testing (vacuum, RF, motion mechanics, cooling, etc.)

8. VELO workshop, Amsterdam, april ‘00M.Ferro-Luzzi Some questions, en vrac Partial bake out of Al box to clean surfaces on the beam side: could we consider baking the box (e.g. at 80-100 ºC) while cooling the stations ? what are the sensitive components in the Si stations ? Temperature cycling of Si stations: What will happen to the Si stations ? Beneficial ? Deteriorating ? (we assume it’s no problem) // commented out... // Water condensation on (cooled) stations: // No problems ? (Si, FEE, bonding, etc.) // Vapour pressure at -30 ºC is 10 -1 mbar  only monolayer. Radiation resistance of carbon-fiber support structures: how good ? Vacuum design: In case one detector half must be turned off, do we want to have the possibility to operate the other half ? Cabling: How many wires in total ? What kind ? cable properties: impedance, attenuation, etc. (what for ? signal, power, control, digital/analog, etc.) How will the grouping be done ?