Transcript ppt

Update on
Intra-tower Alignment
L. Rochester.
I&T meeting
7 October 2005
Checking the signs
Using Michael’s constants for TowerA, I ran a set
of jobs on real data with various combinations of
constants read in with the opposite sign.
In each case, I plot Tkr1KalThetaMS, which
measures the kinkiness of track.
The lower this number, the better we’ve corrected
for misalignments.
Conclusion: the signs are right!
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Overall sign
aligned
not aligned
anti-aligned
3
One translation at a time
aligned
minus X
minus Y
minus Z
4
The Z rotation
aligned
minus X-planes
minus Y-planes
both
It’s easy to get one or the other coordinate wrong!
5
A look at the full instrument
• Michael has provided intra-tower constants for
all 16 towers.
– 8 based on runs at SLAC
– 8 based on runs at Pisa
• We can now characterize the full set of these
constants.
– For each plane, 3 constants are measured
• displacement along measured direction
• vertical displacement
• rotation around vertical axis
– In each tower, constants are adjust so that there are
no overall deformations of the tower.
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Horizontal Displacements
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Rotations around vertical
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Vertical displacements, by tower
The top of each layer is in red, the bottom in black
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Summary of vertical displacements
Distance between top and bottom planes in a
layer is off by 218±8 microns in Gleam geometry
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