To see if there are any smoking guns, fit the U/D (and L/R) lines for the offsets and laser directions, and then look at
The fits were done using solvelist.com and testfit.gp where LR Line 4 failed. I can go back and refit this one, but it would be hard to compare with the others.
For Up/Down (tangential) differences in profiles I have
For Left/Right (radial) differences in profiles I have
Up/Down Offsets. The MAB offsets are not expected to correlate with each other well, since the mounting is so variable. However, the averages of the ME stations may represent relative rotations of the disks wrt the ME+4/ME-4 stations. Divide the numbers by 7.2 to get mrad. Recall that the contribution to the uncertainty due to the profile error is of order 200 microns, and mounting error is (from photogrammetry) roughly of order 1mm. We do not expect the disk warping to change the tangential positions substantially. Perhaps we are wrong.
| Station | Average (mm) |
| ME+1 | -3.9 ± 3.3 |
| ME+2 | -4.0 ± 3.0 |
| ME+3 | -2.9 ± 3.2 |
| ME+2 and +3 | -3.4 ± 3.2 |
| ME-1 | 1.7 ± 1.6 |
| ME-2 | -2.4 ± 1.6 |
| ME-3 | -2.2 ± 1.6 |
| ME-3 and -2 | -2.3 ± 1.6 |
Left/Right Offsets. This requires a little care. The MAB offsets are not expected to match well with anything much, since the MAB mounting is highly variable and the YB0 disk isn't supposed to bend much (by symmetry). However, the ME3 DCOPS radial position should be similar to the ME4 position (taken as fixed in this exercise), while the ME2 and ME1 positions should be similar to each other and be shifted radially farther out. Here we see (or see hints that) the average radial position of ME3 wrt ME4 is about -0.6mm (± 2.3), which is reasonable; but the average of ME2 and ME1 is -4.5 (± 3.0), which seems to be of about the right magnitude (2*2mrad * 1700mm or 1000mm). It is negative, which is to be expected in this case, since the offset isn't the DCOPS offset but the shift in profile position.
So I conclude that these distributions center reasonably.
Modified 11-January-2011 at 10:27
http://hep.physics.wisc.edu/~jnb/cms/10Jan2011
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