me+1 hslm fits

1

James N. Bellinger

University of Wisconsin-Madison

3 December 2008

ME+1 hSLM FitsME+1 hSLM Fits

2James N. Bellinger 3-December-2008

SummarySummary● Fits converge using

• DCOPS data• Link disk fit positions• Link laser sensor data• Z1 (distance to MAB) sensor data

● Field on and field off data from CRAFT● Small bug remains with Z positions


ModelModelZ1 sensor: Transfer plate to MAB

Link laser: prism makes 2 lines

DCOPS laserIlluminates 4 DCOPS

Ignore ME+1/1 in this model

YE+

1MA

B

ME+1/

2

ME+1/

3

Measures ME+1/2Measures MAB

Need to refine Z at this point x 6


Some massaging requiredSome massaging required

There is some drift3.8T

Select an appropriate region, and use the average value.

Raw sensor values forPT1 Z1Distance from Transfer to MAB

Ramping field


PositionsPositions• Photogrammetry targets

• Cocoa Field Off (at end of CRAFT) to PG values• Direct comparison only

• Chamber centers• Field Off to Field On

• Direct comparison only• Field Off to Ideal

• Direct comparison and removing overall shifts• Field On to Ideal

• Direct comparison and removing overall shifts


PG Targets: ME+1/2PG Targets: ME+1/2

1.1mm1.0mm

0.8mm

1.0mm

1.0mm

1.3mm

X Y


PG Targets: ME+1/2 ZPG Targets: ME+1/2 Z

PROBLEM: Inconsistency in the ideal target positions, and Cocoa Z definition.Investigating; should be solved by end of the day.


PG Targets: ME+1/3PG Targets: ME+1/3

0.4mm 0.4mm1.6mm

1.4mm0.7mm

1.0mm

XY


PG Targets: ME+1/3 ZPG Targets: ME+1/3 Z

PROBLEM: Inconsistency in the ideal target positions, and Cocoa Z definition.Investigating; should be solved by end of the day.


Chamber CentersChamber Centers

• Ideal position• Cocoa fit with field on• Cocoa fit with field off• No centers generated from PG targets yet

for ME+1


Chamber centers ME+1/2Chamber centers ME+1/2

Difference between field off and field on fit positions

Center pulled in in Z by 8.1mm


Chamber centers ME+1/3Chamber centers ME+1/3

Difference between field off and field on fit positions

No significant shift in chamber center in Z. Needs check!


Chamber centers in ZChamber centers in Z

Ring 2 fits for Z

Ring 3 fits for Z


Overall ShiftsOverall Shifts• If a ring is rotated, its PG and chamber

positions will reconstruct away from the ideal.

• Direct comparison of PG and COCOA fits is misleading because these rotations aren't taken into account—precision is better than it appears.


Removing Overall ShiftsRemoving Overall Shifts• Want to know shift relative to ring

• Subtract off the overall misalignment of the disk/ring

• Look at relative shifts, esp vs position around ring• Measures variation in relative mounting• MuonGeometryArrange tool

• Calculates shifts of chambers, builds an overall shift of the ring

• Shifts the ring and re-compares chamber shifts• Bug prevents comparing incomplete geometries to

each other


Cocoa vs Ideal ME+1/2Cocoa vs Ideal ME+1/2

Deviations of order mm from field off to field on. NOTE that the scale changes!

Plot of deviations as vectors starting from chamber centers. Scale at top is length of longest deviation.

Remaining deviations after ring realignment


Cocoa vs Ideal ME+1/3Cocoa vs Ideal ME+1/3

Deviations of order 0.1mm from ideal, and from field off to field on


Cocoa vs Ideal ME+1/2 ZCocoa vs Ideal ME+1/2 ZVariation in Z around the ring after ring shift is removed


Cocoa vs Ideal ME+1/3 ZCocoa vs Ideal ME+1/3 ZVariation in Z around the ring after ring shift is removed


Z shifts around ringZ shifts around ring● No obvious pattern to relative Z shifts● Shifts are of order a few hundred microns

me+1 hslm fits

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