Weekly Endcap Alignment meeting 9/7/06:

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Upcoming CMS week:



Dick would like 1 hour of talks on alignment during the EMU meetings

(Mo, Tue 9-1pm CERN time). Suggestion: 3-4 talks. Topics:

Status, MTCC activities, MTCC data analysis, software, ...





Jim:



DCOPS analysis: (see his Sep 7 entry on his alignment web page)



He doesn't understand why the deviations from interpolated line fits

are so large, e.g. for the two B=0 measurements that were taken

before the magnet test and after. Marcus recommends to double-check

with Dave and in Marcus' email updates from CERN as to what shims were

removed when to take this into account properly if not already done

so. We need to know the exact shimming of each DCOPS as used in the

MTCC to make sense of the DCOPS data.





Oleg: 



- From CERN: from Xiaofeng on new analog r/o system in rack PC: 

  Half of rack is done. End of September can switch from old R/O 

  (desktop PC) to new R/O (rack PC) for analog.



- Analysis of analog sensors: 

  (see his ppt presentation that he emailed to the group)



  ME+1 displacement in z is 3-6mm from Keyence Laser 

  distancemeters. 6mm was predicted by ANSYS.

  It appears that the displacement is higher at the top (6mm)

  than at the bottom (3mm). Dick surmises that this might be 

  because the disk is sitting on grease pads.



  Why is it non-linear ?

  Dick notes that YB2 also moves in z and we are actually measuring the

  relative displacement.



  Z-tubes: We would like to see data from 2 unbroken sensors that sense

  a single z-tube on BOTH ends so we can determine how much motion

  ME+2,+3,+4 undergo in z with field on. Not clear if that exists

  in the MTCC data set. Oleg to check.



  PX: Chambers get farther apart from each other as expected.

  Q: What's the Hubble constant for the expansion of the disk?

  However, we do not have a quantitative estimate for this

  effect to compare against, yet.



  ME1-3 chambers that are between "Z-stops", where barrel and

  endcap connect together appear to show more displacement (50-60 micron)

  than those near a z-stop (30 microns)



  Lots of discussion to interpret the inclinometer data. Need to

  validate the data to understand exactly what rotations and what

  directions are monitored by what inclinometers. Not that all clinometers

  are mounted parallel to the floor, i.e. in the CMS x-y plane.   



  Std. Temp. sensors show lower temperatures (19-21 deg C) than temp.

  sensors on DCOPS (30 deg C). Is that because they are directly mounted

  to the colder iron ?