Minutes BWS Upgrade: Electro-Mechanical Design Meeting #12 -- 13th July 2016 --

Participants: Raymond Veness, Bernd Dehning, Federico Roncarolo, Jonathan Emery, Patrik Andersson, Jose Luis Sirvent

Agenda ( https://indico.cern.ch/event/543918/)

1. Communications (R.Veness)

• PSB ECR already launched and progressing on the aproval
• Forks 2-3 units are out of tolerances. The work has to be redone, which would delay the pieces availability to end of August.
• For mounting test (on august) 1 of these fork will be modiffied to fix the tolerances with some bricolage.
• The error comes from a perpendicularity deviation Shaft-Fork.
• The assembly test will be performed in August and the device plans to be available for functional testing on September.

2. Alxion Standard and Special Motor testing (J. Emery)

• Tested Alxion Standard and Special version with modiffied airgap (300V)
• Back-EMF normal version: Show nice results and 1% deviation respect to specs
• Back-EMF special version: Show also nice reults with 4% deviation respect to "estimated" specs.
• Not clear if special version was tested by Alxion before procuring specifications or they approximated by calculations
• Speed and profiles tests with Special Alxion show satisfactory results with Dspace, calculated torke ~ real required torke
• Problem found after motor testing:
  • Appeared after the week-end (test finished Friday, problem appeared Monday)
  • Motor generates a extrange noise even when not moving and holding position
  • Effect is not symetrical, appears in In & Out Scans but seems stronger in Out scans.
  • Currently trying to work out the reason:
    • During movement the currents are showing a extrange behaviour
    • Motor dismounted, visual inspection (Dmitry) show no frictions
    • Isolation on phases seems not to be the problem, tests show that they're ok.
    • Cross-Check wiht Parker motor--> No problem seen
    • Test with older compiled code --> Problem still seen
    • Generator Mode --> the output voltages are Ok
  • Next steps:
    • Try standar Alxion
    • Try another Alxion stator 300v
    • try standar rotor.
  • For the moment the reason still unclear.

3. PSB Acquisition system: Intallation proposal (J.L. Sirvent)

• Installation requirements: 1 Functional system (PSB standard) + 1 Test flexible test platform (Independent systems)
• Base line is acquisition on surface , both options send their analog signals to surface
  • In PSB short cables & long bunches --> Fine for BW point of view (bunch pile-up)
  • Gain in noise reduction << Risk of failure of acquisition Front-End for radiation exposure
  • In any case allow installation of a Front-End for testing pourposes
• The idea is to procure a operational (PSB) system 100% available for functional validation
• Allow space & cabling flexibility to test different scintillator + photo-detector configurations
  • Standard Cylindrical 30x30mm
  • New Rectangular 100x100x10mm
  • MaPMT, HPD, Filterweels
  • Space reservation for 1 Front-End
• 3 Set-up Configuratoins show using the same cabling requirements.
• High dynamic range acquisition system (no required filter / pmt gain tuning)
  • Strategy 1. HPD + QIE10/12 (1e5)
  • Stregety 2. MaPMT + ICECAL (1e5)
  • Stragety 3. MaPMT + 2 x QIE10/12 (1e7?)
• New mechanics required to procure for both assembies:
  • FilterWeels
  • PMT/MaPMT/HPD shielding
  • Scintillator/Waveghides holder
  • Supports
  • All these details are not included on ECR
• Studies on PSB needed to:
  • Estimate required dynamic range on PSB
  • Adjust acquisition systems working point
  • Cross-Check PSB simulations
  • Check possible improvements by changing Scintillator Geometry
  • Check Light yields on scintillator per impacting proton on wire (for different energies/intensities)
• Proposed ways to proceed:
  • Trust on simulations ? Check with Roberto Rocca.
  • Estimate light yield trough measurements stored on measurements DB
  • Prepare measurement campaign new systems when installed.

4. Comments from Dundee Visit (R.Veness)

• Some issues were identiffied thanks to the visit
• Residual material observed on measurements:
  • It reduced the reflectivity on some disk areas
  • Comes from some abrasive liquid used for finishing the laser slits.
• Smooth transition Reflective/Non Reflective
  • Such smotth transition did not allow enought "flat" reflective area between slits
  • Sample and laser are in a fix position, Laser scans the disk by angular movements
  • Laser loses focal point, which produces wider slits
• For Dundee Equipment, 20 um width slits was already on the limit (we asked for 10um slits)
• The fabrication of full size disk would produce worst slits due to equipment configuration
• Dundee required XY Stage + Controller system (and maybe new laser) to produce high quality slits.
  • Estimated Cost > 10KCHF
  • In collaboration with other sections and other uses foreseen, if required cost may be splitted by 3.
  • Jose's remarks:
    • With commercial company we reach the results required for the slits.
    • Does it worth it? we'd need a guarantee that this new equipment would produce better slits than commercial.
    • In any case, the sensor weak point is the surface quality (roughness, defects, reflectivity)
    • Instead of spending time/money in building very spensive disk it may worth it to improve the sensor robustness with some minor mofifications for metallic disks usage (more scaning dots / different configuration).