10-Nov-2005US ATLAS Tracking Upgrade Santa Cruz 1

10-Nov-2005 US ATLAS Tracking UpgradeSanta Cruz

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Staves: An Integrated Tracking Structure

for the IDCarl Haber


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Outline

• Issues from Genoa– Derived specifications

• Progress on Phase 1 program

• Plan for future work


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Genoa Meeting

• Basic configuration “consensus”– Pixel region

– Intermediate region: 3 SS layers 3cm x 80m

– Outer region: 2 DS layers ~10cm x 150m, • Z measurement provided by stereo

• Radiation issues: implication for S/N and operating temperature– ~-25C suggested

• Strong emphasis on material and services reduction: alternate powering schemes


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Basic Genoa Layout

0.000

20.000

50.000

100.000

0.0

00

10

0.0

00

10

0.0

00

20

0.0

00

20

0.0

00

pixel region


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2 Types of Staves

• 20<R<50cm: 1 meter stave, 6.4 x 3 cm strips, alternate along Z, top/bottom provides full coverage

• R>50cm: 2 meter stave, 6.4 (12.8) x 12 cm strips, axial/stereo – top/bottom design to provide Z at large radius– Width driven by economics and electrical issues (voltage drops…)

16 modules/side

18 modules/side


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Mechanical Core


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Stave End View

Hybrid electronics

Peek Cooling channels 2.9 x 5.6 mm

Silicon Sensors4mm separation

Material/stave: • 1.8% RL •(compare 2.5% ATLAS)• 124 grams

Fraction of Total RL:• Hybrids 13%• Sensors 39%• Bus Cable 17%• CF/Coolant 29%

Carbon Fiber Skin

Foam Core


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Integratedsupportstructure:

2 int bulkhead3 outer bulkheads2(3) barrels


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Structure with oneouter barrel andmaximum of 1 meterunsupported staves


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Details of CDF Bulkhead

See stave core mechanical samples


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Stave Specifications

• Electrical– Power distribution– Signal transmission– HV

• Mechanical: advocate a monitored approach with software corrections implicit. There are many examples of large scale precision systems done that way.– Accuracy in plane– Sag effects– Operating temperature and gradients


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Property Short stave Long Stave

width 6.4 cm 6.4 cm (12.8 cm)

length 98 cm 192 cm

detector width 6.4 cm 6.4 cm (12.8 cm)

detector length 3 cm 12 cm

detectors per side 18 16

gap between detector along the stave 2.4 cm 3 mm

detector thickness 280 microns 300 microns

number of strips 768 384 (768)

strip pitch 80 microns 160 microns

Power in front end chips 3 watts 1.7 watts (3.3 watts)

Power in silicon – no dose 1 milliwatt 1 (2) milliwatt

Power in silicon – high dose 1 watt 1 (2) watt

Maximum temperature at silicon -25 C -10 C

Maximum temperature variation <5 C <5C

Max detector position shift from nominal y 30 microns 30 microns

Max detector position shift from nominal x 30 microns 30 microns

Survey accuracy Sy 5 microns 5 microns

Survey accuracy Sx 10 microns 5 microns

Survey accuracy S 0.13 mRad 0,13 mRad

Ladder sag maximum 250 microns 500 microns

Ladder sag stability 50 microns 50 microns


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Operating Temp – S/N

• At Genoa values quoted -15 to -25 C

• Depends on how the spec’d S/N (10?) is achieved, many variables at play– Leakage current vs dose well known– Silicon thickness– CCE, orientation (n in p, n in n, p in n)– Strip pitch: cluster size, capacitance– FE noise, integration time


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Continued…

• p bulk gives us high field at collection, good for CCE issue

• Wide pitch (150 um) gives us large volume for current generation (bad) but favors single strip clusters (good), and lower capacitance

• Fast electronics allows us to reduce integration time (good for shot noise) but has larger series noise (bad, but how bad?) and required more power (bad for cooling).

• Etc….


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Comments on Monitoring

• Stave sag and other deformations (temperature) will be present

• Position monitoring and readout should be designed into the system from the start.– A number of precise and long range position

sensing technologies are commercially available

• We should be prepared to apply software corrections to the alignment extensively


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Phase 1 Stave•An ATLAS version of the CDF Run2b device•1 sensor + hybrid = 1 module (hybrid glued to Si)• 6 modules per side• Modules linked by embedded bus cable and readout token passing scheme• 2 sided – axial/stereo or axial/axial• 1 Interface Card /stave• Total length 66 cm• 6144 channels /stave•Built around carbon fiber/foam laminate

Purpose is do demonstrate low noise multi-module performance with ATLAS electronics


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Phase 1 Milestones (completion dates given):full electrical specification and schematic for Phase 1 stave 10/04 doneestablishment of test stands at LBNL, BNL, and Hampton 11/04 donevalidation of test stand operation on test parts 12/04 donedesign and layout of Phase 1 hybrid 12/04 donefabrication of hybrid 03/05 doneassembly and test of hybrid 04/05 donere-commission and tests with existing fixtures 03/05 doneassembly of ATLAS staves 06/05 11/05initial test of ATLAS staves at LBNL 07/05 11/05transfer to and test of staves at BNL/Hampton 08/05 12/05irradiation studies of staves 10/05 02/06transfer of assembly methods to BNL 07/05 12/05


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Bus cable detail shows bonding region

The bus cable runs UNDERNEATH the sensors. Connections to the hybrids made with wirebonds in small Z gaps between consecutive crystals

Bus cable is copper/kapton/Al laminate with 100 micron lines/spaces and thin Al shield layer

Electrical isolation of bus from detectors by grounded shield and diagonal traces (not parallel to strips)


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ABCD Hybrid

• Fabricated in BeO• Fine pitch (100 micron)

etched line-work• 7 micron Au thickness• Bond to pc card for test• Re-bond on stave• No connectors• Schematic similar to

standard SCT hybrids• Electrically OK• 64 fabricated


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Module Assembly/Hybrid Mount


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Module Test

Conducting rubber


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Main Technical Issue: Clock Distr.• Existing bus cable design: individual clock/com to each of 6

modules• This was at the edge of practicality (layout)• Genoa: long staves with N ’modules• Prefer to use a multidrop configuration

– This may be the only practical solution for longer staves– Stave bus cable has been redesigned, layout revision in progress– Timing and reflections have been studied– Implications for ABCD-Next design, etc.


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Bus Cable Geometry and Impedance

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1~10.7

1

2

CF

Cu

ADHESIVE

KAPTON

Materials: Al foil 2mil, Dupont LF0100, Shinetsu CA333 2 mils, Cu 18 um,Kapton 1 mil, Adhesive

Al

>>Matches measured impedance


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Issue of timing

• Hybrid stubs = 12 pf

• LVDS risetime = 3.5 ns

• Bandwidth = 0.35/3.5 = 100 MHz

• Impedance of hybrid stub due to capacitance• 1/(2pi * 100 MHz * 12 pf) = 130 ohms

• Propagation time = 60 ps/cm (3 ns for 50 cm)


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Measurements

• Literature available on LVDS multidrop performance– Application reports from TI,

National, Fairchild…– TI study of 36 receivers

• Need to understand this configuration as part of the ongoing study– Significant impact on

cabling


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Bus Cable Test75

termination 12+12

40 MHz, at pos 1

-4.00E-01

-3.00E-01

-2.00E-01

-1.00E-01

0.00E+00

1.00E-01

2.00E-01

3.00E-01

4.00E-01

1 54 107 160 213 266 319 372 425 478

Series1

ref1 at pos 1

40 MHz at pos 3

-3.00E-01

-2.00E-01

-1.00E-01

0.00E+00

1.00E-01

2.00E-01

3.00E-01

4.00E-01

1 56 111 166 221 276 331 386 441 496

Series1

ref2 at pos 3

40 MHz at pos 5

-4.00E-01

-3.00E-01

-2.00E-01

-1.00E-01

0.00E+00

1.00E-01

2.00E-01

3.00E-01

4.00E-01

1 57 113 169 225 281 337 393 449

Series1

ref 3 at pos 5

40 MHz, No Bus

-4.00E-01

-3.00E-01

-2.00E-01

-1.00E-01

0.00E+00

1.00E-01

2.00E-01

3.00E-01

4.00E-01

1 50 99 148 197 246 295 344 393 442 491

Series1

No Bus


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Implications

• Bus cable test results imply that Phase 1 test stave with 6 hybrids (4 ABCD chips/hybrid) will probably work with a single clock line.

• For large N staves need to consider an LVDS receiver chip at the hybrid input to reduce capacitance seen by the bus drivers

• This is consistent with reduced services model– AC coupling– Regulators– Current monitor– Addressing issues (A.G. note)

• The module receiver chip (MRC) definition and specification should become an important aspect of the ABCD-next discussion.


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Continued Activity FY06• Complete Phase 1 stave

– Apply a multidrop configuration• Alternative powering: add to a second version of the Phase 1 stave

– Serial– DC-DC?– Study of bussing and system issues.

• Development of stave readout electronics– Evaluate performance of SCTDAQ for multi-module tests

• Development of detectors– BNL is pursing the 3 cm design

• Study of mechanical concepts for long staves – Bill Miller– Material– Geometry, cross-section– Cooling– Fabrication

• ABCD-next– MRC definition?


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Complete Phase 1 Stave

• Fabricate bus cable

• Continue fabrication and test of remaining hybrids and modules

• Assemble and test 2-3 staves for LBNL and BNL, Hampton

• Costs within FY05 funding


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Alternate Powering• Development of specs (LBNL)• Add serial powering test to the Phase 1 stave

– New version of the bus cable (LBNL)– Add power interface hybrid (LBNL, RAL)– Use commercial components

• Investigate a “universal” configuration for serial and DC-DC tests (LBNL)

• System issues – bypass, failure, noise (BNL)


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Readout System

• Need to understand how well current UK test stand works for multi-module staves tests, issue of concurrent operation

• Alternative is a simple pattern generation approach similar to LBNL “Patt Board” developed by MGS for CDF

• Engineering on this would be done at BNL and is included in FY06 budget


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Detectors

• To go beyond the Phase 1 stave based upon CDF Run2b surplus detectors required ATLAS specific devices

• Candidate is the 3cm short strip design

• BNL will do a design and fabricate.

• For the outer stave the CDF devices may still be useful – need to do inventory and availability


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Mechanics

• 1m and 2m designs require new ME effort for design and fabrication– Laminates– Boxes– Extrusions

• Low temperature operation• Materials• B.Miller effort – LBNL• Fixture studies – LBNL (FNAL connection)• BNL engineering• RAL engineering


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Conclusions/Actions

• Complete phase 1 stave– Near term

• Develop serial powering modification to stave– Summer 06

• ABCD-next effort– Define interface aspect, MRC

• Continue mechanical studies– Include monitored alignment concepts

• Develop test detectors for phase 2 stave• Readout electronics study


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R500.000

R1000.0004.6°


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10-Nov-2005US ATLAS Tracking Upgrade Santa Cruz 1