1. Alignment of the CMS Tracker
We have 4 mechanically separated components: TIB, TOB, 2 x TEC
To start the pattern recognition process we need to know the position of the silicon detectors with an accuracy of 0.1mm.
After the reconstruction of tracks we will align the Si-detectors with tracks to mm accuracy.
CERN, Tracker Meeting
Stefan Schael, I. Phys. Institut, RWTH Aachen

2. Stefan Schael, I. Phys. Institut, RWTH Aachen
For the endcap we have 9 disks with 16 petals.
CERN, Tracker Meeting
Stefan Schael, I. Phys. Institut, RWTH Aachen

3. Alignment Concept II: Internal Tracker Alignment
Ray 1 is the link to the muon system nm laser, position monitor: Si-Detectors placed on 6 petals on the last three disks of the TEC. Position accuracy relative to the silicon detectors 0.020mm. r = 345 mm
CERN, Tracker Meeting
Stefan Schael, I. Phys. Institut, RWTH Aachen

4. Mini Alignment Disk (MAD)
the MAD is divided into two parts, to be removed during the installation of the pixel detector.
the MAD is mechanically connected to the TEC with 6 CF-Tubes, 30 mm diameter, 3 mm wall thickness, centered at r=345 mm.
Maximum weight of the MAD 12 kg, maximum distance 120 mm from the TEC.
we need 3 different short periscopes to mach the 6 folded symmetry of the muon system to the 16 petals in the TEC
we need to put 12 Si-Detectors on the MAD to monitor the position of the incoming laser beam.
R=345 mm
CERN, Tracker Meeting
Stefan Schael, I. Phys. Institut, RWTH Aachen

5. Stefan Schael, I. Phys. Institut, RWTH Aachen
CERN, Tracker Meeting
Stefan Schael, I. Phys. Institut, RWTH Aachen

6. Stefan Schael, I. Phys. Institut, RWTH Aachen
CERN, Tracker Meeting
Stefan Schael, I. Phys. Institut, RWTH Aachen

7. Stefan Schael, I. Phys. Institut, RWTH Aachen
CERN, Tracker Meeting
Stefan Schael, I. Phys. Institut, RWTH Aachen

8. Stefan Schael, I. Phys. Institut, RWTH Aachen
Ray 2 and 3 are used for the internal endcap alignment nm Laser. r = 564 mm and r = 1045 mm, 8 back petals We have to remove the metallisation from the backside of the si-detectors.
Ray 4 connects TEC-1, TEC-2, TOB and TIB
CERN, Tracker Meeting
Stefan Schael, I. Phys. Institut, RWTH Aachen

9. Stefan Schael, I. Phys. Institut, RWTH Aachen
CERN, Tracker Meeting
Stefan Schael, I. Phys. Institut, RWTH Aachen

10. Stefan Schael, I. Phys. Institut, RWTH Aachen
Position of the alignment channels for ray 4 in the inner shell of the outer barrel:
CERN, Tracker Meeting
Stefan Schael, I. Phys. Institut, RWTH Aachen

11. Stefan Schael, I. Phys. Institut, RWTH Aachen
Error Budget
0.010 si-wafer  frame
0.020 frame  petal
0.020 petal  disk
0.010 laser position measurement
Assumption for simulation: mm
accuracy for each point.
We can reconstruct the position of the disks with 0.03 mm accuracy.
CERN, Tracker Meeting
Stefan Schael, I. Phys. Institut, RWTH Aachen

12. MC simulation of the tracker alignment system
CERN, Tracker Meeting
Stefan Schael, I. Phys. Institut, RWTH Aachen

13. Stefan Schael, I. Phys. Institut, RWTH Aachen
Experience from AMS
CERN, Tracker Meeting
Stefan Schael, I. Phys. Institut, RWTH Aachen

14. Stefan Schael, I. Phys. Institut, RWTH Aachen
CERN, Tracker Meeting
Stefan Schael, I. Phys. Institut, RWTH Aachen

15. Measurements with CMS Si-Detectors in Aachen
=1064 nmm
beam diameter 1.5 mm
pitch 50 m
d(det1-det2) 4 cm
no anti reflective coating
CERN, Tracker Meeting
Stefan Schael, I. Phys. Institut, RWTH Aachen

16. Stefan Schael, I. Phys. Institut, RWTH Aachen
systematic variation of the position measurement due to thickness variation in the si detector
position accuracy +/ mm
CERN, Tracker Meeting
Stefan Schael, I. Phys. Institut, RWTH Aachen

17. Stefan Schael, I. Phys. Institut, RWTH Aachen
Summary
We have a new concept for an alignment system for the CMS tracker which is compatible with the new layout of the tracker.
It monitors the relevant parameters of the tracker support structure with < 0.1 mm accuracy (MC simulation).
We have proven that we can monitor laser beams with si detectors with <0.01 mm accuracy.
CERN, Tracker Meeting
Stefan Schael, I. Phys. Institut, RWTH Aachen