November 11 SESAPS 2006 Samir Guragain 1

Calibration, Installation & Calibration, Installation & Commissioning of Sensors for Commissioning of Sensors for

the Alignment of the Alignment of Muon Endcap Chambers in the Muon Endcap Chambers in the

CMS ExperimentCMS ExperimentS. GURAGAIN, M. HOHLMANN

Dept. of Physics, Florida Institute of Technology,

Melbourne, FL 32901

November 11 SESAPS 2006 Samir Guragain 2

An OverviewAn Overview• Introduction of the system

• Sensor calibration method and result

• First commissioning results

• Summary & conclusion

November 11 SESAPS 2006 Samir Guragain 3

CMS Detector of LHC @CERNCMS Detector of LHC @CERN

Magnetic field 4 Tesla The CMS solenoid 13 m long with an inner diameter of 6 mTotal weight 12500 t The largest superconducting solenoid ever madeOverall diameter 15 m 3 Endcap disks and 4 layers on each side.Overall length 21.6 m

-Z

November 11 SESAPS 2006 Samir Guragain 4

Transfer plate

R-sensors

Z-sensors

Note: only smallsample of analog sensors shown

ClinometersTransfer plate

DCOPS

ME Alignment System ME Alignment System

The system monitors the positions of Cathode Strip Chambers relative to each other and to the MABs.

The alignment uncertainty should be comparable to the chamber resolution and it is defined as 75 m for ME1/2 and 150 m for the others stations.

November 11 SESAPS 2006 Samir Guragain 5

Calibration method & resultCalibration method & result

Linear mover

Prec. dowel pins

Precision Reference Bar

-4

-2

0

2

Sen

sor R

espo

nse

(V)

18161412Distance (cm)

Sensor Response vs Distance

Distance (cm)

Typical Z sensor Response (ME1)

Sens

or R

espo

nse

(V) Results

Sensor response vs distance &

Ratio of sensor response to ref.

Volt vs distance are linear.Slope = 1.0062 V/cm

Error in slope = 0.00039 V/cm

Acceptable Error

Proximity sensor

November 11 SESAPS 2006 Samir Guragain 6

Installation & Commissioning Installation & Commissioning at CERNat CERN

Cross hair Laser adjustment to pass it through four CCDs in each DCOPS on Straight Line Monitor (SLM)

November 11 SESAPS 2006 Samir Guragain 7

First commissioning resultsFirst commissioning results

• In summer 2006, all the sensors and readout were installed and commissioned on four positive endcap layers.

• The detector was closed up and the huge 4 T solenoid magnet of CMS was turned on for the first time ever in Aug-Sep, 2006.

• Data during the magnet test phase I & II were logged successfully at different B-field

plateaus and have been analyzed.

November 11 SESAPS 2006 Samir Guragain 8

Z sensor data analysis & Results Z sensor data analysis & Results on axial chamber displacementon axial chamber displacement

MTCC (Aug 26-28)

0.0

1.0

2.0

3.0

4.0

5.0

8/25 8/26 8/27 8/28 8/29

Mag

netic

fiel

d, T

esla

ME+1 Station (Z1 laser sensors)

-1

0

1

2

3

4

5

6

7

8/25 8/26 8/27 8/28 8/29

Dis

plac

emen

t, cm Point 2

Point 5

Point 6

P1

P2

P3

P6P5

P4

ME+1 Station (Z1 sensors)

y = 0.0307x2 + 0.0309x - 0.0007

y = 0.2806x2 + 0.1414x - 0.0081

y = 0.2646x2 - 0.1985x + 0.0057

0

1

2

3

4

5

6

7

0 1 2 3 4 5Magnetic field, Tesla

Dis

plac

emen

t, m

m,

Point 2

Point 5

Point 6

Poly.(Point 2)Poly.(Point 5)Poly.(Point 6)

Z1

Finite element analysis predicts a distortion in Z-direction of endcap disks (outer edges) for about 6 mm that is in good agreement with Z1 laser displacement sensor data for upper point 2 but for lower point 5 and 6 the disk bend deformations are less than predicted. Quadratic dependence with magnetic field was observed

6 laser displacement sensors were mounted on theYE+1 disk but only 3 MABs on YB+2.

Z

B(T)

Dis

plac

emen

t (m

m)

November 11 SESAPS 2006 Samir Guragain 9

Wire extension potentiometer

-800

-600

-400

-200

0

0.0 1.0 2.0 3.0 4.0 5.0Magnetic field, T

Dis

plac

emen

t, m

Point 1

Point 2

Point 3

Point 5

Point 6

ME+1 StationR3 Sensors (between chambers)

-400

-300

-200

-100

0

0.0 1.0 2.0 3.0 4.0 5.0Magnetic field, T

Dis

plac

emen

t, m

Point 1

Point 2

Point 3

Point 4

Point 5

Point 6

ME+3 Station R1 Sensors (between chambers)

0

50

100

150

200

0.0 1.0 2.0 3.0 4.0 5.0Magnetic field, T

Dis

plac

emen

t, m

Point 1

Point 2

Point 3

Point 4

Point 5

Point 6

ME+2 StationR1 Sensors (between chambers) At 4.0 T:

•The largest displacement between chambers (ME+1 station) does not exceed ~ 700 m

• Chamber displacement relative to transfer plates at outer edge is small (100-150 m)

Displacements between inner/outer chambers: ME+1: neg. sign => disk face compressed ME+2: pos. sign => disk face expanded ME+3: neg. sign => disk face compressed

P1

P2 P3

P4

P5P6

R2R3

R sensor data analysis & Results R sensor data analysis & Results on Radial displacementon Radial displacement

November 11 SESAPS 2006 Samir Guragain 10

Capacitive fluid level monitor

-4

-2

0

2

4

0 1 2 3 4 5 6 7Point #

Tilt

angl

e, m

rad

Station +1

Station +2

Station +3

Station +4

Average

Theory

Bending angle for ME+1-4 stations at outer edge

Magnetic field = 4.0T

outer edge

inner points

-6

-4

-2

0

2

4

6

0 1 2 3 4 5 6 7Point #

Tilt

angl

e, m

rad

Incl-1XIncl-2XTheoryTheory

ME+1 StationTilt angle measurements at 4.0T

The bending angle for station ME+1 is larger closer to the center (~ 4 mrad) than at the outer edge of the ME+1 disk (~2.5 mrad).

Inclinometer data analysis & Inclinometer data analysis & Results on tilt angle displacementResults on tilt angle displacement

Z-stop

Disk Deformation:

The current under-

standing of yoke disk

deformations due to

magnetic forces based

on these clinometer

measurements

November 11 SESAPS 2006 Samir Guragain 11

-200

0

200

400

600

800

8/25 8/26 8/27 8/28 8/29

Dis

plac

emen

t, m

Px1/1

Px1/2

Px2/1

Px2/2

Px3/1

Px3/2

Px4/1

Px4/2

Px5/1

Px5/2

Px6/1

Px6/2

ME+1 Station

Sector #4

-200

0

200

400

600

800

8/25 8/26 8/27 8/28 8/29

Dis

plac

emen

t, m

Px1/1

Px1/2

Px2/1

Px2/2

Px3/1

Px3/2

Px4/1

Px4/2

Px5/1

Px5/2

Px6/1

Px6/2

ME+1 Station

Sector #5

-200

0

200

400

600

800

8/25 8/26 8/27 8/28 8/29

Dis

plac

emen

t, m

Px1/1

Px1/2

Px2/1

Px2/2

Px3/1

Px3/2

Px4/1

Px4/2

Px5/1

Px5/2

Px6/1

Px6/2

ME+1 Station

Sector #6

0.0

1.0

2.0

3.0

4.0

5.0

8/25 8/26 8/27 8/28 8/29M

agne

tic fi

eld,

T

Magnet Tests (Aug 26-28, 2006)

B (T)

0

200

400

600

800

0.0 1.0 2.0 3.0 4.0 5.0Magnetic field, T

Dis

plac

emen

t, m

PX2/1

PX2/2

Poly.(PX2/2)Poly.(PX2/1)

Proximity Sensors monitor the distances between the outer ring of muon chambers on station 1. This is the only ring where chambers do not overlap and tracks cannot be used to interpolate between SLMs. Distances between these chambers increased with magnetic field and reached up to 700 m at 4.0T.

Azimuthal displacements vs. B:Azimuthal displacements vs. B:

Proximity sensors

PX sensor data analysis & Results PX sensor data analysis & Results on azimuthal displacementon azimuthal displacement

November 11 SESAPS 2006 Samir Guragain 12

DCOPS beam profileDCOPS beam profile

• 2048 pixels per CCD

• 14 μm pixel pitch

Digital linear CCD-based Optical Position Sensor (DCOPS) with 4×1-d CCDs

CCD 2 CCD 4

November 11 SESAPS 2006 Samir Guragain 13

Summary & conclusionSummary & conclusion• About 400 analog sensors were calibrated precisely at

Florida Tech and shipped to CERN for the installation.

• The performance of the sensors up to 4T solenoid magnet during the test was good and they clearly indicated the flexing of the large absorber disks.The results are in good agreement with the finite element analysis predictions.

• Now half of the system is ready to go into the underground cavern for final position of the detector.