Present : Steve B, Victoria, Jaroslaw, Melissa, Ed, Jason, Paul Soler. and John Cobb
Minutes and action items

Alignment of quadrupoles

*Requirement is to align the magnetic axis of the quadrupoles with respect to the nominal beamline

*The question is how well we know the location of the nominal beamline.

*Nominally the quads are aligned better than 200 microns according to engineering drawings however,

*noone can remember where the nominal beamline actually came from. If we knew this, we could try to
survey in the quads (although there is no magnetic map of the quads. An OPERA simulation of the fields
does exist so we should use that)>

*MICE note 216 contains much information on the preliminary alignment of the beamline components.

*John made the point that we don't know what our sensitivity to the exact position of the beamline components
actually is. Maybe we are worrying about an effect that is actually small. Steve proposed to look at
varying the position of the quads and seeing what the effect would be for a nominal beam. Ed and a student
will work on this after Ed's holiday.

*Jason thinks he knows the nominal beamline location from the beam dump and will try to work it out ASAP.

Action Items : Understand nominal beamline : Jason and survey team
Understand effects of moving quads around from simulation : Ed, student

Alignment of USS/DSS/FC to magnetic axes

  • John presented work he has done on the sensitivity of the experiment to errors in the alignment of the magnetic
    axes of the USS, DSS and CC for STEP VI.
  • He suggests that we need to know the alignment of the solenoids and focus coils to less than 0.5 mm, and the
    coupling coils to less than 0.25 mm in Step VI. Suggests we assume the same for Step IV.
  • In principle we can work out the location of the cryostats to within 0.5 mm before the PRY goes in. The location of
    the coils relative to the cryostat have already been surveyed to that precision.
  • Roy will check to see where there might be time in the schedule to do a survey of the beamline elements before
    the PRY turns up.
  • Chris points out that we can get a good estimate from the survey, and can refine that with fits to beam data.

Action Items : Check schedule to see when we can survey USS,DSS and FC. : Roy


  • Melissa reported that the tracker alignment plan is currently being discussed. The tracker group has the
    start of a plan but need to develop it.
  • Other detectors will be surveyed in after PRY installation. Given the coarse pitch of the PID detectors, a 1mm resolution
    on alignment is considered acceptable and doable.

Updated by Boyd, Steven over 9 years ago ยท 4 revisions