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FF 20130409

Present:

  • Chris Rogers
  • Henry Nebrensky
  • John Palin

During visit to MICE hall:

  • Discussion on survey data
    • Survey produces xit format which appears to be proprietary binary format - requires Spatial Analyzer tool developed by New River Kinematics www.kinematics.com; DL survey crew have a licence, Jason Tarrant may also have a licence.
      • What if they go out of business?
    • Each new survey results in a new xit file
      • No clear dissemination/back up policy on these files
      • Outline agreement that copies of these should be stored on MOM laptop which is backed up
      • either emailed to MOM after each survey, or MOM can put them on a USB stick before surveyor leaves RAL
    • Did not discuss how survey should be documented; but documentation is probably required
    • Established that the survey coordinates are either left-handed or right-handed (and a conversion is not trivial) - but not which one. Presumably this comes through from the CAD model anyway.
  • Discussion on survey details
    • Centre line D2-MICE-beamline
      • X axis (D2-MICE-beamline) defined by least squares fit to quadrupole mirror-plate apertures for Q4-9
      • define line-on-floor by looking at reference points on floor - brass plate under D2; floor target(sticker) in front of Q4; floor target(sticker) below the Ckovs
      • Z axis is defined by fitting to plane that includes line-on-floor and D2-MICE-beamline; and taking a line in that plane that is perpendicular to D2-MICE-beamline
    • Some discussion - how do we get a handle on where D1-D2 line is pointing wrt D2-MICE-beamline?
      • Proposed measuring around solenoid exit aperture and taking the mean to get a handle on solenoid downstream end placement
        • This requires removing the Proton Absorbers and possibly GVA1; hope to do this within the pneumatic proton absorber upgrade process. Hopefully PA apertures would end up aligned on beam centre
      • No clear technique for getting the upstream end placement
      • Noted that it was not clear that the D1-D2 line sits in the x-y plane as defined above; and this should not be assumed (if possible)
    • And finally
      • Emphasised that of all beamline components, TOF positions are most crucial to measure well.
For reference, note that the surveyor's co-ordinate system for the MICE Hall and Cooling Channel is as follows:
  • X is along beamline with beam travelling in positive direction
  • Y is across beamline; positive points south (towards MLCR)
  • Z is vertical with up in positive direction