h1. 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