1. Transfer Line and CSC Rφ Reconstruction
James N. Bellinger
University of Wisconsin-Madison
6-December-2009
James N. Bellinger 6-December-2009

2. Data Most of the Transfer Line lasers are well aligned.
The best illuminated is Line 1, and the worst is Line 2
The following shows Line 1
All data used in this report is 3.8T from an event in October
One DCOPS reading failed and was replaced with another from a run 8 hours earlier
James N. Bellinger 6-December-2009

3. DCOPS along Transfer Lines
Mounted on MABs
Minus Endcap
Plus Endcap
CMS Z
James N. Bellinger 6-December-2009

4. Transfer Lines: Positions2
6 Transfer Lines
of 12 DCOPS
Lasers at ME+4
and ME-4
shine axially
Establish
relative X,Y
of the transfer
plates, and thus
the SLM ends 3
SLM example 1 4 Y 6 X 5
James N. Bellinger 6-December-2009

5. DCOPS Sensors with Laser
A crosshair laser (a pair of lasers
each shining through a cylindrical
lens) illuminates each of the
DCOPS in turn along the line
DCOPS
Laser
James N. Bellinger 6-December-2009

6. Transfer Line DCOPS
Up/Down CCDs measure Rphi, either in positive or negative direction depending on the DCOPS orientation
Left/Right CCDs measure radial positions
Transfer Lines are independent of each other
UP CCD
RIGHT CCD
LEFT CCD
DOWN CCD
Radius direction
James N. Bellinger 6-December-2009

7. Purpose of Transfer Lines
Outer MAB positions are defined by Link wrt the tracker body
Using Outer MAB positions to define lines in space, determine where the Transfer Plates are in space
Using Transfer Plate positions determine the positions of the measured Endcap chambers
Determine an outer position on the Inner MABs as a cross-check for the Barrel
James N. Bellinger 6-December-2009

8. Transfer Line 1, Laser 1 Laser
Plus Endcap
MABs
Minus Endcap
CCD 1 and 3 are top two rows. They measure Rphi
CCD 2 and 4 are bottom two rows. They measure R
The red curve is the fit to the profile
At each station (column) at least one profile within each pair is good
James N. Bellinger 6-December-2009

9. Transfer Line 1, Laser 2 Laser Plus Endcap MABs Minus Endcap
CCD 1 and 3 are top two rows. They measure Rphi
CCD 2 and 4 are bottom two rows. They measure R
The red curve is the fit to the profile
At each station (column) at least one profile within each pair is good
James N. Bellinger 6-December-2009

10. Photogrammetry and Drawings
PG measured the disk centers
PG measured the Transfer DCOPS position wrt. the disk center
The relative position of points on the Transfer Plates was taken from drawings
James N. Bellinger 6-December-2009

11. Locating the Transfer Line
Link can give the outer MAB positions in (x,y,z) wrt a tracker body reference
PG gives us an estimate of Z for the Endcaps
Still working on Z-sensor reconstruction
Combining these can give us (x,y,z) for measured chambers
James N. Bellinger 6-December-2009

12. Simple Use of the Transfer Line
The Link information gives us fixed points in space (in principle 12) to tie the 6 Transfer Lines to the tracker. With lines fixed in space we can use averages of Transfer Line positions on each disk to estimate disk rotations
James N. Bellinger 6-December-2009

13. Radial Fits From Cocoa Yellow lines locate DCOPS apertures
Notice that the
hit and fit to
the hit are close.
The fits are
good.
How good?
Plus laser
Minus laser
Green circles are measured hits
Red diamonds are fit hits
Error bars are
too small to
see
James N. Bellinger 6-December-2009

14. Summary of Fit Residuals
Line
Up/down = Rphi
Left/right = radial 1
950 µ
310 µ
2 Poor illumination
1.74mm
1.31mm 3
1.82mm 4
430 µ
680 µ 5
660 µ 6
560 µ
Left/Right CCDs are illuminated by one pair of laser fans, and
Up/Down CCDs are illuminated by the other pair. I look at
them separately here.
In Transfer Line 3 one of the lasers is not perfectly aligned, and
in 2 both sets need adjustment.
The next slide plots both types of CCD residuals together.
Oleg finds
110µ with
extra data
quality cuts
James N. Bellinger 6-December-2009

15. Laser Fit Residuals for Line 1
Tight central
core of well-
measured
points: 120 µ
Scattering of
less good
points.
Core fit agrees
with Oleg
RMS=490 µ
Measured-Fit in mm
James N. Bellinger 6-December-2009

16. CCD Measurement Consistency
If neither of a pair of CCDs is shadowed, they provide independent measurements of the laser position at that point, subject to
Tilting of the transfer plate
expected to be small
Tilt of the laser fan itself
measured in Cocoa, ignored here
Variation in CCD position within the DCOPS
of order 100 µ RMS
James N. Bellinger 6-December-2009

17. Compare RAW CCD measurements for Line 1
CCD1-CCD3 or
CCD2-CCD4 if
both in a pair
have good
profiles.
Only 28 of 48 do,
the rest have one
side shadowed.
RMS =310 µ
includes laser tilt
and calibration
variation!
Difference between CCD measurements, mm
James N. Bellinger 6-December-2009

18. Disk rotations
Averaging the reconstructed DCOPS centers on each disk gives me rotations of the disks.
Knowing MAB positions wrt tracker means these should be real rotations
James N. Bellinger 6-December-2009

19. Disk rotation results Independent measurements of the same disks.
Station
Rotation in phi about Z (mrad)
Distance of shift (mm)
RMS of shifts (mm)
ME+4 (YE+3)
-0.45
-3.3
2.9
ME+3 (YE+2)
-1.16
-8.4
2.2
ME+2 (YE+2)
-1.00
-7.2
2.1
ME+1 (YE+1)
-0.81
-5.8
ME-1 (YE-1)
0.35
2.5
6.7
ME-2 (YE-2)
-0.73
-5.3
3.8
-0.344
-2.5
5.9
ME-3 (YE-3)
0.19
1.3
3.6
Independent measurements of the same disks.
YB+2 and YB-2 MAB positions are the references.
James N. Bellinger 6-December-2009

20. Chamber Positions
We generated ZCMS positions and YLocal rotations for all CSC for CRAFT09 data
Himali has been studying XCMS /YCMS CSC positions
Machinery is in place to generate positions for measured CSC once we validate the Transfer Line reconstructions with PG
σ=159µ
The rest are similar
James N. Bellinger 6-December-2009

21. ME-4 SLM1 Chamber Rφ Shifts with Field Off/On
Animated GIF
Will not work in
PDF
Average Shift=20µ
Relative CMS Rφ (mm)
Plots from
Himali
James N. Bellinger 6-December-2009

22. Summary
The positions of the Transfer Plates are reconstructed to within about 500µ for most lines. We think we can do better.
Ready to reconstruct chamber positions as soon as group approves Transfer Plate positioning
Transfer Line 2 laser tweaking will improve the data
James N. Bellinger 6-December-2009

23. BACKUP MATERIAL
James N. Bellinger 6-December-2009

24. Transfer Line 2, Laser 1 (worst)
Profile shape is odd
No connection to far
station
Harmless glitch: I used
data from earlier event here
James N. Bellinger 6-December-2009

25. Transfer Line 2, Laser 2
No connection to U/D for two farthest stations
James N. Bellinger 6-December-2009