1 June 20021 June 2002 Workshop on b/tau Physics at LHC, HelsinkiWorkshop on b/tau Physics at LHC, Helsinki 1

CMS Tracker CMS Tracker

Hardware Alignment Hardware Alignment

Goals of TK hardware alignment

Concept

General layout

Internal TK alignment External TK alignment (LINK)

Hardware

Conclusions

A.Ostaptchouk, RWTH-AachenA.Ostaptchouk, RWTH-Aachen

1 June 20021 June 2002 Workshop on b/tau Physics at LHC, HelsinkiWorkshop on b/tau Physics at LHC, Helsinki 2

Goals of Hardware Alignment Goals of Hardware Alignment

Internal alignment: 100 m measurement of Si-module relative positions for track pattern recognition (recent H.Voss and B.Schwering results: 1000 m ! t.b.c.) 10 m monitoring of Si-module positions stability for track parameter reconstruction

External alignment:

100 m measurement of TK position w.r.t. MS 20 rad measurement of TK orientation w.r.t. gravity both for joint TK+MS track fit

1 June 20021 June 2002 Workshop on b/tau Physics at LHC, HelsinkiWorkshop on b/tau Physics at LHC, Helsinki 3

Concept of Hardware Alignment Concept of Hardware Alignment

1. No dedicated optical sensors Collimated laser beams with ~ 1060 nm produce signals directly in the TK Si-modules

2. No external reference structures All the elements of the alignment system are mounted directly on the TK parts

3. No precise positioning or aiming of beam collimators Number of measurements redundant enough to reconstruct detector positions without knowledge of laser beam initial parameters

4. Minimal impact on the TK layout and production technology The effected tracker parts are as uniform as possible

1 June 20021 June 2002 Workshop on b/tau Physics at LHC, HelsinkiWorkshop on b/tau Physics at LHC, Helsinki 4

General Layout of Alignment System General Layout of Alignment System

Internal alignment:

eight Ray 2 and eight Ray 3 beams per TEC align forward wheels, monitor 50% of petals

eight Ray 4 beams align end-caps and barrels w.r.t. each other

External alignment:

six Ray 1 beams per TEC align TK w.r.t. MS

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Internal Alignment ImplementationInternal Alignment Implementation

Laser beams through End-Caps

Laser beams through Barrels

holes in supports (petals, wheels)

holes in back-side metallisation of Si-sensors (2500/24000)

structure gaps in TOB inner shell

alignment tubes inside these gaps fixed on TOB support discs

1 June 20021 June 2002 Workshop on b/tau Physics at LHC, HelsinkiWorkshop on b/tau Physics at LHC, Helsinki 6

Internal Alignment SimulationInternal Alignment Simulation

Track residuals in End-CapsTEC: before applying alignment corrections RMS = 1.1 mm TEC: after applying alignment corrections RMS = 27 m

Track residuals in BarrelsTOB: after applying alignment corrections RMS = 49 m TIB: after applying alignment corrections RMS = 85 m

1 June 20021 June 2002 Workshop on b/tau Physics at LHC, HelsinkiWorkshop on b/tau Physics at LHC, Helsinki 7

orientation of TK w.r.t. gravity is determined by precise measurement of TEC back-disc orientation w.r.t. TEC wheels and gravity It requires back-disc instrumentation with Si-modules at radius of ray 2 and tiltmeters

Concept of External Alignment System

position of TK w.r.t. MS is determined by precise measurement of continuous laser beam positions inside TK and MS (LINK)

On TK side it requires: 2D-sensors on TEC petalsperiscopes inside TEC back-disc

External Alignment ConceptExternal Alignment Concept

1 June 20021 June 2002 Workshop on b/tau Physics at LHC, HelsinkiWorkshop on b/tau Physics at LHC, Helsinki 8

External Alignment ElementsExternal Alignment Elements

2D-sensor made of two Si-modules

Periscope mountedinside TEC back-discInstrumented TEC back-disc

1 June 20021 June 2002 Workshop on b/tau Physics at LHC, HelsinkiWorkshop on b/tau Physics at LHC, Helsinki 9

External Alignment SimulationExternal Alignment Simulation

TK-MSpos - precision of TK position w.r.t. MS

is defined by measurements of 6 laser beams (ray #1) inside the TK volume:

• r-positions of laser beams w.r.t. TKr 20 m• -orientations of laser beams w.r.t. TK 20 rad (characteristic distance between TK and MS L 5 m )

TK-Gori - precision of TK orientation w.r.t. gravity

is determined by two independent factors:• back-disc orientation w.r.t. TEC (measured by 8 laser beams, ray #2)BD-TEC 10 rad • back-disc orientation w.r.t. gravity (measured by 4 tiltmeters, requires their calibration w.r.t. back-disc fiducials)BD-G 10 rad

TK-G

ori = BD-TEC BD-G 20 rad

TK-MS

pos = r L 100 m

1 June 20021 June 2002 Workshop on b/tau Physics at LHC, HelsinkiWorkshop on b/tau Physics at LHC, Helsinki 10

Hardware:Hardware:Experience from AMS-1 Experience from AMS-1

1 June 20021 June 2002 Workshop on b/tau Physics at LHC, HelsinkiWorkshop on b/tau Physics at LHC, Helsinki 11

Hardware:Hardware:Experience from AMS-1 Experience from AMS-1

Si-module transparency (@ = 1064 nm) is about 20 – 25 %Beam spot position resolution is better than 10 m

1 June 20021 June 2002 Workshop on b/tau Physics at LHC, HelsinkiWorkshop on b/tau Physics at LHC, Helsinki 12

Hardware Hardware 1D Si-Modules (Ray 2&3)1D Si-Modules (Ray 2&3)

1D Si-modules for Ray 2&3 are the standard Si-modules of the TEC Rings 6&4 (both sides polished plus hole)

1 June 20021 June 2002 Workshop on b/tau Physics at LHC, HelsinkiWorkshop on b/tau Physics at LHC, Helsinki 13

Status of LINK Elements Status of LINK Elements 2D Si-Modules (Ray 1)2D Si-Modules (Ray 1)

2D Si-modules are made outof two standardSi-modules fromRing 1 & Ring 2(wafers W1 & W2)

1 June 20021 June 2002 Workshop on b/tau Physics at LHC, HelsinkiWorkshop on b/tau Physics at LHC, Helsinki 14

Hardware Hardware Optical WafersOptical Wafers

Table of optical wafers

Wafer typeWafer type

Total numberTotal number

of TEC wafersof TEC wafers

(+5% cont) (+5% cont)

AdditionalAdditional

alignmentalignment

waferswafers

SpeciallySpecially

treatedtreated

waferswafersCommentsComments

W6bW6b 1008 (50)1008 (50) 1818 140140 Hole Hole 10mm 10mm

Both sides polishedBoth sides polished

W6aW6a 1008 (50)1008 (50) 1818 00 ____________

W4W4 1008 (50)1008 (50) 00 420420 Hole Hole 10mm 10mm

Both sides polishedBoth sides polished

W2W2 576 (29)576 (29) 3030 3030 Hole Hole 28mm 28mm

Both sides polishedBoth sides polished

W1W1 288 (14)288 (14) 3030 3030 Hole Hole 28mm 28mm

Both sides polishedBoth sides polished

LINK wafers Internal alignment wafers

Production of optical wafers:

Additional alignment wafers are included to the general order for Hamamatsu

The company will polish their both sides and will produce holes in metallisation Prototypes will be delievered in July 2002

If they are OK (transparency, electrical properties), all the optical wafers – in Fall 2002

1 June 20021 June 2002 Workshop on b/tau Physics at LHC, HelsinkiWorkshop on b/tau Physics at LHC, Helsinki 15

Status of LINK Elements Status of LINK Elements PeriscopesPeriscopes

Periscope mountingscheme:3 very hard balls2 CFC platforms3 hardened Al inserts

1 June 20021 June 2002 Workshop on b/tau Physics at LHC, HelsinkiWorkshop on b/tau Physics at LHC, Helsinki 16

Status of LINK Elements Status of LINK Elements PeriscopesPeriscopes

Two options for the periscope design:

Hollow CFC body with mirrors glued on it (Aachen) Single piece of quartz with mirror coated edges (Spain)

Requirements for the periscope mounting/housing:

Reproducibility: position 20 m orientation 100 rad Cold-warm transition: inside TK volume -10o C outside TK volume +20o C

1 June 20021 June 2002 Workshop on b/tau Physics at LHC, HelsinkiWorkshop on b/tau Physics at LHC, Helsinki 17

Status of LINK Elements Status of LINK Elements TiltmetersTiltmeters

Current choice:

Wendor: Applied Geomechanics Serie: 756 (Mid-Range) Total range: 10 degrees Resolution: 1 rad Repetability: 2 rad Environmental: -25o C to +70o C, 0 to 100% hum. Sensors: 2 tilt , 1 temp Dimensions: 41x51x25 mm3

1 June 20021 June 2002 Workshop on b/tau Physics at LHC, HelsinkiWorkshop on b/tau Physics at LHC, Helsinki 18

Test PlansTest Plans

StageStage CommentsComments ResponsibleResponsible DateDate

Optical wafers

Both sides polished

Hole in metallisation

Hamamatsu Sep 2002

Alignment

modules

Bonding, mechanical & electronical assembly

Aachen Nov 2002

Laboratory

tests

Transmittion,reflection,

resolution

Aachen May 2003

Beam tests DAQ, combined particle

& optics data analysis

Aachen Oct 2003

Test of Optical Si-Modules

1 June 20021 June 2002 Workshop on b/tau Physics at LHC, HelsinkiWorkshop on b/tau Physics at LHC, Helsinki 19

Test PlansTest Plans

StageStage CommentsComments ResponsibleResponsible DateDate

Prototype

option I

Hollow CFC body with

two mirrors glued

Aachen

Islamabad

March 2002

Prototype

option II

Solid transparent body

with two edges coated

Spain 2002

Mounting

platforms

Suitable for both options Aachen Summer 2002

Tests Cold-warm transition,

4 sensors, support

Aachen

Spain

Spring 2003

Periscopes

calibration

Phogrammetry method

CERN facility

Spain

Aachen

Summer 2003

Test of Periscopes