star silicon tracking detectors svt and ssd

[email protected] CBM Workshop on Silicon Detector Systems, April 18-20 at GSI Darmstadt 1

STAR silicon tracking detectorsSVT and SSD


Summary of the talk

• Few words about STAR experiment and SVT

• Design of the SSD and its elements

• Ladder and barrel assembly

• Installation

• Improvement for ALICE ITS


• Few words about STAR experiment and SVT• Design of the SSD and its elements• Ladder and barrel assembly• Installation • Improvement for ALICE ITS


Collision of two gold beams


STAR detector


Average radiation length : 4.5%X0 incl. fee cards

SVT Design

3 Barrels :• Inner at 6 cm

•8 ladders – 4 wafers/ladder• Middle at 10 cm

•12 ladders – 6 wafers/ladder• Outer barrel at 15 cm

•16 ladders – 7 wafers/ladder

Length : 42 cm216 wafers

waferFEE


SVT installation in summer 2001





• Installation



Silicon Strip Detector


The purposes of the SSD

• To enhance the STAR tracking performances due to its position resolution and its dE/dx capabilities.

• To facilitate the connection of the TPC tracks and the hits in the SVT, being closer to the TPC.

• To improve the tracking efficiency in the central region especially in the low momentum domain and for secondary particles.


The SSD for STAR

20 ladders16 modules per ladder491520 analogue channels1 square meter of double sided waferRadiation length : 1.1% X0Length : 1mDiameter : 46 cm

z = 740 m

r = 20 m


SSD Ladder


Design of the module

Silicon Wafer

TAB

Hybrid Circuit


Design of the silicon wafer

Double sidedStereoscopic angle : 35 mradThickness : 300 umActive area : 40 mm x 73 mm768 strips per side Pitch : 95 umN strip insulation : P sprayBiasing scheme : punch-throughOperating voltage : < 50VMarks for positionningManufacturer : Eurisys


Readout chip : ALICE128C60

00µ

m

8700µm

Specifications :

• AMS 1.2 um

•Input range : 13 MIPs

•Gain : 50mV/MIP

•340 uW/channel

•Noise : 290 e- + 8 e-/pF

•JTAG controlled

•Internal pulse generator


TAB tape

This technique has multiple advantages :• handling of the chips is easy, • test is possible in realistic conditions •Flexibility allowing 3D connection•Pitch adaptor•Industrial standard


ALICE128C on a TAB tape


Module production flow


Detection Module


Detection Module

464 modules produced with a yield of 82%


SSD performances

S/N – Pside = 30

S/N – Nside = 20

Digital resolution :

•20 μm in transverse plane

•740 μm in Z axis


Carbon frame


Ladder cables and connection

3M Z-Axis Adhesive Films


30 MHzBLVDS bus

Readout chain

One Readout boardReadout board :•Interface of the barrel to Slow control, Trigger and DAQ•Located on the TPC wheel

Ribbon cable (1m)

shielded cable (2m)

3 MHzon a ladder

10 ADC+C2D2 boards

16 modules (P or N side)

C2D2 board :• Interface modules/ADC board (analogue signal multiplexed)• reference voltage• Temperature measurement• Latch-up control• Bypass module, zero filling instead• Technology : board-Flex-board

ADC boards :• interface Readout boards/ladder• power supply distribution•Analogue to digital conversion


SSD cooling system : principle


SSD Cooling system : measurement results

10 W

3 W

3 W

33.1oC

33.7oC

27.6oC

33.2oC

30.7oC 24.5oC

25.1oC

30.9 oC

27.8 oC

19oC

29oC


Power supply of one ladder

4 amperes fuse

CAEN A525 power supply

+2V 0V


+2V 0V


0V 35V


0V +2V


0V +2V


+5V 0V


0V +5V

Detector

Front end electronics

Front end electronics

ADC Boards Connection Board

+35V 0V

0V +2V -2V +35V +37V +33V

+2V 0V 0V -2V

0V

-2V

+3V

+37V

+35V

+35V +33V

+35V +33V +38V

ADC Boards Connection Board

16

JWS300-12 power supply

+ 7 V 0V

+7V

0V

JWS300-12 power supply

0V 7V

+7V

0V Readout Board

Readout Board 0V

0V +35V

+5V

0V

+5V

One ladder

P side low voltage power supply (floating) N side low voltage power supply (floating)

Biasing voltage

Power supply of the readout board and the non floating part of the ADC board





• Installation



Ladder assembly flow

One ladder /week• 3 persons• First ladder : 3 weeks• 3 last ladders in 1 week (5 persons)

Ladder frames

Module placing on the assembly bench

Visual inspection

Placing and gluing the carbon ladder on top

of the modules

Soldering of the cables to the module

Functional and Noise test

Ladder cables

Visual inspectionElectrical test

Packaging and storage until barrel assembly

Modules

Visual inspectionNoise test

ADC & C2D2 boards

Visual inspectionElectrical test

Ladder pre-assembly

Functional and Noise test


Ladder assembly


Ladder views


Sector assembly


One sector


SSD database

You can visit it at :

http://wwwstar-sbg.in2p3.fr/index.php





• Installation



SSD installation


Milestones of the project

• Design started in 1997

• Technical proposal approved in 1998 by STAR

• Five modules prototypes in 2000

• First ladder produced and installed in 2002

• first half installed summer 2003

• Installation completed in summer 2004





• Installation



Semi-automatic assembly bench


Graphic user interface


Soldering bench


ENDThank you

star silicon tracking detectors svt and ssd

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