Alignment constants of the FPix in CMS Detector.
(Mike Roman, Greg Derylo, Mikhail Kubantsev, Bruno Gobbi. July, 2004)
SiDet, Sept. 05, 2005
See also: 305-v9, 402-v1, 406-v1
Alignment of what relative to what:?
of Pixel Disks relative to Pixel Barrel, SiTK, and Muon System
Premises:
the final tracking is always done with tracks,
needed is some input from survey data to facilitate the process
Q: What information is available to align the Pixels to the CMS detector?
A: Sensors of the Pixel Disks have fiducials. Their position can be traced
to the CMS detector through the Service Cylinder installation feet.
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D:\cms\mech\align\presentation-sidet.ppt
One must trace the position of the
Pixel Sensors
Survey
½-Disks
Survey
½-Service Cylinder
Have fiducials
200 µm
Mech.
Survey
CMS Detector
Have alignment balls
Installation Pins
2
D:\cms\mech\align\presentation-sidet.ppt
Fiducials on FPix Sensors
Fiducials
1 x 1 sensors
Kim Jiolo, June ’03. This picture is
obsolete.
See Doc. 406-v1
D:\cms\mech\align\presentation-sidet.ppt
60 µm full size
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Alignment Balls on ½-Disks
Accessibility of Balls with
Objective tested at SiDet
with old and new Adapter
Board.
D:cms\mech\align\ball_1_3_4-c.ppt
4
Obstructions (?) to the survey caused by the new
Adapter Board
Adapter Board
D:\cms\mech\align\presentation-sidet.ppt
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Limited access to the survey fiducials on the Plaquettes (overlap of Panels).
Also limitations caused by the Adapter Board. See Greg Derylo.
D\:cms\mexh\alignm\12-may_1-c.ppt
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Proposed Survey Plan
½-Disk assembled and not installed in ½-Serv. Cylinder
0 The ½-Disk is located flat on the surveying equipment.
1 The coord. System of the ½-Disk is determined by two reference holes
machined in the Outer Ring. Survey with touch probe.
2 Measure optically on one side (3 Panels or 4 Panels) of the assembled
½-Disk, the position of a few (visible) sensors fiducials on each
Plaquette of the 12 Panels.
3 Also measure optically the position of the “Alignment Balls” on the same
side of the ½-Disk (on Inner and Outer Ring).
4 Measure with a touch probe the alignment of the “Alignment Balls” (on
Inner and Outer Ring) of the same side of the ½-Disk. The use of objective
or touch probe are interchangeable without distorting the measurements.
5 Repeat the same measurements on the other side of the same ½-Disk.
6 Set now the ½-Disk in a vertical plane. With the touch probe measure the
position of the Alignment Balls on both sides of the ½-Disk.
The ½-Disk is now surveyed!
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Proposed Survey Plan, cont.
After all the ½-Disk have been installed in the four ½-Serv. Cylinders,
(electrically) tested, and perform as designed,
each ½-Disk will be surveyed relative to the Installation Pins of the ½-Serv. Cyl.
We believe that the position of the “Alignment Balls”, on the ½-Disk, can be
Surveyed with the touch probe after the Disk have been installed in the
½-Serv. Cyl. and tested. (This has not been tried with the model.)
1 For each ½-Disk installed in the ½-Serv. Cyl. Measure with the touch probe,
the position of the Alignment Balls (on inner and outer rings) on both
sides of the ½-Disk. Also relate each set of measurements to the 4 pins
used to install the ½-Serv. Cyl.in the CMS detector. (Slide #2)
It is estimated that the ½-Serv. Cyl. position relative to the CMS detector
will be known to about 200 µm. (This number depends from the length of
the ½-Serv. Cyl. And the installation rails.)
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Proposed Test of Survey ½-Disk CMS-Pixel
June 30, 2004
(Mike Roman, Greg Derylo, Michael Kubantsev, Bruno Gobbi)
1.
Coordinate system of the1/2-Disk is determined by a hole machined in the outer ring on the x axis.
1.
Survey sequence:
1. Survey position alignment balls on ½-Disk without Panels. Survey both sides together.
Use touch probe.
2. Install Panels on both sides with detectors (paper) and fiducial marks (pattern to be
decided).
1. Survey optically 4 fiducials on each Plaquette (Fiducials specified as 4 corners of a
rectangle) in coordinate system reconstructed from alignment balls.
2. Survey with touch probe the fiducial balls on both sides of the ½-Disk and then both
sides at same time. This step takes place in the carbon fiber of the half-cylinder.
Cables/plumbing mockups needed to test accessibility to survey balls on downstream
of the half-disk.
It is expected from this test:
a) Choose survey equipment (optical, touch probe)
b) Ensure a collision free survey path.
c) Decide optimal sequence of measurements.
d) First experience with file of data.
e) First coarse survey result for the model.
f) Determine the extend of the effort to survey the Disks
D:\cms\mech\mod\meas\surv-mod-fpix.ppt
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