The Intermediate Silicon Layers detector

OUTLINE•ISL inside CDFII

•Why the ISL?

•Conceptual Design

•Ladders and Spaceframe

•Rasnik Online Alignment System

(6“ Sensor technology will be shown in the next talk)

DPG Frühjahrstagung

Heidelberg, 15. - 19.März 99

•Frank Hartmann

Institut für Experimentelle Kernphysik

Der Silizium Zwischenlagen-Detektor fürDie Erweiterung des CDF Detektors am Tevatron

THE CDF II DETECTOR

& THE ISL

The ISL

SVXII (Silicon Vertex) + Layer00

3 barrels 5 layers 12 wedges Radii 2.45 - 10.6

cm layer 0,1,3 90o

layer 2,4 + 1.2o

Layer00Beyond baselineRadius 1.6 cm

Why the ISL?

•High momentum resolution combined with COT ||<1

•Fine granularity helps to resolve ambiguities in dense track environments (e.g. in stiff jets t t )

•ISL & SVXII combined provide a precision standalone silicon tracking system with up to 7 axial and 7 stereo measurements

•Adds forward tracking (1<||<2)

pT resolution:

impact parameter:

Add. Spacepoint --- R=10.6 and 40 cm

COT

md 200

1)/(%4.0 cGeVpTp

p

T

T

ISLSVXII

Distribution of primary vertices (z)

ISL Conceptual Design Considerations

Simple design, limited R&D

Take advantage of SVXII R&D

• use the same electronics and DAQ.

Take advantage of the large radial position of the layers

• less radiation ==> S/N can be lower ==> more surface area of Silicon per readout channel.

• hit density is much lower ==> larger strip pitch and relaxed mechanical tolerances.

Material: 0.5% rad. length (central region)

1% rad. length (forward region)

1% rad. Length (hybrids, endcaps, cooling) ?

ISL System Components

•~ 888 large area, double sided silicon microstrip sensors.

• 303 104 total channels

• 512 strips on each side with a pitch of 112m

• Strips on one side have a stereo angle of 1.2 degrees

• Sensors grouped into readout triplets called ladders

• Each ladder has double-sided AlN readout hybrid.

• Sensors and hybrid are supported by a carbon fiber shell.

• 296 Ladders are paired to form 148 modules.

• Modules installed on Carbon fiber supports to form barrels.

• ISL Barrels are assembled into a space frame

• Operational temperature 10-150C ; water cooling (chilled water)

ISL

3 * 900 layers

4 * 1.20 layers

Mechanical design of the spaceframe

195,2 cm

•RINGS: Carbon fiber

•RODS: Hollow carbon fiber

•No direct connection to carbon fiber ladders, only to hybrids

•FEA: gravitational sag 20mu

•Weight 7 kg

Every second ladder displayed

Radii:

~20cm

&

~30cm

Spaceframe: Al Prototype

Forward Barrel

mechanical ladder dummies

Final carbon fiber rods(hollow)

Spaceframe Assembly

Expected final precision

50mu overall

ISL Ladder Design and Mounting (1)•max rigidity & min material due to carbon fiber design

•Full rigidity reached with sensor gluing

•Geometry allows easy microbonding

Wedge shape to max rigidity

ISL Ladder Design and Mounting (2)

Position precision dependent on silicon only, alignment hole on hybrid

Hybrid tower (rotating)

with precision pin

3 silicon sensor towerwith teflon

(x,y,rotating)

Al support for the carbon ladder

Highprecisionbearings

•Ladder will be placed on Al support beneath the teflon planes.

•Silicon sensors will be positioned in respect to the hybrid‘ precision hole.

•Glue will be put on carbon fiber ladder.

•Support and ladder will be elevated to connect ladder and silicons.

z-stages

Rasnik: The Online Alignment System (1)

CCD image of the mask

shields

shields

•Coded Masks - Lenses - CCDs Movement of one part induces a

shift in the mask-image in the CCD.

•Online Alignment check

•Submicron range

IR

Rasnik: The Online Alignment System (2)

•Cheap alignment system

•Simply controlled and readout with one PC

Conclusion

2/%4.0 TpTp

•The ISL is a relatively young project (starting OCT. 96)

•ISL/SVXII allows standalone tracking•

•Most Spaceframe parts are ready and partially mounted•Mounting fixtures are ready•MICRON as well as HAMAMATSU are delivering silicon sensors•Hybrids are in production•First prototype ladder has been built and is working •Preproduction will start next month•Engineering RUN spring 2000; DATA TAKING fall 2000

)1200//////(20

%4.0

0

2

mLmd

T

T

p

p

DetectorConfig.

Single b tageff.(%)

Double b tageff.(%)

SVX‘+CTC 37.6+-1.0 6.9+-0.5

SVXII+COT 46.7+-1.1 8.7+-0.6

SXVII+ISL+COT

60.1+-1.0 15.1+-0.8