Minutes BWS Upgrade: Electro-Mechanical Design Meeting #14 -- 19th September2016 --

Participants: R. Veness, F. Roncarolo, J. Emery, P. Andersson, D. Gudkov, W. Andreazza, J.L. Sirvent, C. Vulliez

Agenda( https://indico.cern.ch/event/569130/)

1. Post Mortem of the SPS BWSRE Incident and Intervention:

1.1 Causes of the Incident (J.Emrey, F.Roncarolo)

• An error (glitch) occurred during testing BWS Prototype without beam in the processing of the shaft position.
  • Problem never seen on lab. tests and cause under investigation.
  • Error tricked control system to believe that shaft position was off by multiple turns forward.
  • Position control spin the scanner backwards multiple turns to compensate (the wrong measured) position
  • Multiple turns broke kapton wires (for wire continuity measurement).
  • One wire was projected on the middle of the beam pipe causing loses that leaded to beam dumps.
  • Around 14 turns recorded backwards with a speed of 150rad/s (max speed reachable by scanner system)

• Same firmware than Dec 2015 testing, the only difference is the triggering system used
  • New system installed to make synchronous triggers
  • Intended to synchronize scan movement with machine cycle and acquisition system.
• Mitigation plans:
  • 1. Firmware release to avoid more than 2 turns
  • 2. Code re-factorization for noise immunity.
  • 3. Possible usage of optical sensors for control improvement
  • 4. Galvanic ground separation with external systems.
  • 5. Extensive testing of SPS proto located on 867 proposed.

1.2 Intervention and current situation (R. Veness, W. Andreazza)

• Friday night (9/09/2016) Scanner was removed from its tank.
• The tank was closed with a blank flange.
• Some vacuum leakages identified during operation (Flange & gasket out of tolerance)
• The re-installation of the instrument without kapton wires was agreed.
• It was observed a hard point, and some noise, during manual movement.
  • After some manual movements, the noise / hard point, disappeared (residuals on ball bearings?)
• Scanner was installed and tested on Wednestay (14/09/2016).
  • Movement show correct behaviour.
  • One of the two optical sensors seems to have been damaged.

2. Status of work on the PSB Prototype:

2.1 Mechanics (G.Gudkov)

• PSB prototype assembly tests performed on CW37.
• Mounting readiness at 75%, the mounting continues during CW38.
  • No major assembly problems observed so far.
• Disk status:
  • 3 Complete disk produced (Diamond turning)
  • Tests shown not a good performance (material grains)
    • Material current disk AW-2219 (T851), previous successful Samples AW-6082 T6
  • Actions:
    • Manual polishing improved signal quality, but not significantly.
    • New disks will be produced with AW-6082 T6 (VDL)
    • Production 4 disks, 8 Weeks delay, 5000e order this week
    • Laser engraving postponed
  • New possibilities:
    • Glass ring grazing on aluminium disk is being considered
    • Information is being gathered, temperature constraints.
• Scintillator assembly:
  • No spare components, no 2d/3d drawings available
  • Model remade 80% design optimization considering commercial components
  • Filter wheels commercial components need to be defined for design finalization.
  • Filter wheels are used in all machines with same design:
    • Required to produce spares
    • Agreed to produce 1 per machine + for new acquisition prototype.
    • A total production of 10 filter wheels was agreed.

2.2 Electronics and controls (J.Emery)

• Systems:
  • DSpace lab system:
    • Ready for SPS and PSB scanner tests
  • Custom FPGA systems for SPS:
    • 1 system BA5 Ready test
    • 1 system 865 Ready installation
    • 1 system for FW development
  • Analog signals from Optical sensors available (scope)
• Ongoing Developments:
  • New inverter board (P. Andersson)
  • FPGA FW is being modified for PSB (minor changes) (J. Emery)
  • Intelligent drive <--> VFC board communication (C.Vulliez)
  • 4 new control systems for next year VFC V2 based (to see availability).
• Assembly requirements:
  • Fork must be aligned to motor N pole as SPS, resolver must rotate.
  • For electrical feedthrough, time required with the scanner to develop procedure.
• Cabling:
  • Request for PSB and PS planned to be pull this YETS.
  • New surface racks will be installed on PSB.

2.3 Acquisition chain (J.L. Sirvent)

• Scintillators assembly Set-Up:
  • Squared Scintillators available.
  • Cylindrical scintillators ordered and coming.
  • Mechanical housing being designed.
  • MaPMT ordered
  • All components available on 1st November for assembly
• Filter Wheel Status:
  • Currently used Transmission coefficients --> 20%, 5%, 2%, 0.5%, 0.2%, Cardboard, Metal
  • Usage of commercial components (Thorlabs) for filter holders and fixation on disk (Threaded)
  • Proposed the usage of 25mm diam filters (smaller than 30mm currently used)
  • Requested to stick to 30mm, further search in providers required.
  • Proposed to procure 3 complete sets (2 for PSB + 1 for laboratory).
• Acquisition system requirements for PSB (as SPS BA5):
  • PC + 2 PicoScopes
  • 1 VME HV power supply with remote control
  • 2 Filter Wheel controllers
  • 3 Units (Europa Crate) for Back-End prototype
  • Access to turn clock for data tagging.
• Laboratory PMT tests campaign being prepared:
  • Instrumentation ready for tests
  • To check filters
  • Waiting MaPMT, but can tests with Sune's PMTs
  • Still to define testing protocol.
• SPS News:
  • Big noise observed on PMT cable (synchronous with the beam), not so big on pCVD Diamond line
  • Amplifier box considered the possible cause
  • Access on SPS during Stop to remove amplifier box and attach directly the CK50 cable (Signal looks better now).
  • New Matlab-Based Expert application for Acquisition system (now tests are easier).

3. First look at milestones for the series: (R.Veness)

• PSB Prototype installation in EYETS (End 2016)
• PS Prototype installation (end 2017)
  • Location 54, A scanner will be removed to leave place.
• Large series for production envisaged (2019-2020):
  • Proposed numbers --> 8 PSB, 5 PS, 5 SPS + spares
  • Need to agree on numbers (maybe 6 for SPS "H/V")
• Take into consideration the work load for next years
  • Consider the request manpower, lab space...etc.
  • Single tender procurement needs to be justified or market survey done for very expensive parts.