LSWGSeptember 2012

M. GilchrieseLBNL

September 5, 2012

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Introduction• What’s new on pixel upgrades at LBNL in the last year?

– Very little– Will very briefly summarize where we are but for those that

remember….not much new– Severe funding limitations and other work commitments have

precluded progress• Progress on “pixel electrical staves”

– Brief summary– No feedback on mechanical design from this yet.

• New ideas – see Bill’s talk– Enhanced emphasis from DOE for industrial connection– Funding source for additional work– Broader than ATLAS upgrades

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Many Pixel Upgrade Prototypes Made

70cm long, active stave ready for modules

Electrical cable inside foam

1m stave, cable on top, dummy module heaters

One of dozen or so 12cm prototypes, some-co-cured partly

Section of bent stave(20o)

1m I-beam

Disk section prototype

“Co-cured” inner stave(UK)

1.4m long, with cables

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I-Beam Section• Since last meeting, I-beam section, with fiber wrapped Ti

tube, co-cured made and thermally tested, including after thermal cycling (no change)

• Similar technique used for flat short prototypes, same result• Penalty (for wrapping in fiber) is 20% increase in effective

thermal resistance compared to without fiber

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Prototype Results Summary• Diverse prototypes constructed using same building blocks: CO2

cooling, Ti tube, conducting carbon foam, carbon fiber• After extensive thermal cycling – no change in thermal performance

within measurement errors demonstrated on many prototypes.• After irradiation to 1 GRad, thermal performance (including

representative module adhesive) degrades by < 10%• Many prototypes made but not enough to address manufacturing

(particularly reliability) issues and trade off between reliability and material.

• Reasonable agreement between modeling (FEA and other) and prototype results. Although refinements needed, decent predictive capability in place.

• Still waiting for overall design constraints (supports, access) to guide more detailed design.

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“Modules”

Two types of “digital modules” (chips and hybrid, but no sensor” have been used.

Both are rudimentary prototypes to get first experience 4-chip flex VERY rudimentary 2-chip flex, based on IBL, less rudimentary, but only 2 chips Real modules with sensor tile bump bonded to 4 readout chips will

be soon available, but no flex hybrid yet.

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Outer Staves with Embedded Cable

1 electrical half-stave and 1 full stave made with the 2010 cable design Half stave at LBNL, has been used for initial electrical test of noise performance. Full stave is at Bonn, getting ready to use for serial power chain test with 2-chip

modules Next version of stave cable was launched at last years mechanics meeting, but

has suffered many cable fabrication delays and is not yet integrated in any stave We finally have electrical cables in our hands – see next page. Will incorporate

into first stave soon (stave- made by Allcomp- has been ready for nearly a year) The electrically sound cables are 2/3 of the intended length (this was necessary

to get them fabricated successfully) This is not a fundamental problem (we hope). Will be able to make longer cables

in the future. This was done to salvage the present prototype cycle.

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CablesTop: Electrically active, length was limited by manufacturer. To beused in next generation electrical stave at LBNL and Bonn. But needto make “short” staves just for this purpose.

Bottom: Not electrically functional, mechanical use. About 61 cm long.For use in existing Allcomp long stave (parts).

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Existing electrical staves

FULL (at Bonn)

HALF (at LBNL, some testing underway)

Pixel Stave Cable Stauts -- M. Garcia-Sciveres

10Sept, 2012

How new cables fit in stave

11Sept, 2012 Pixel Stave Cable Status -- M. Garcia-Sciveres

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Cables• Key mechanical issue to evaluate is reliability of rigid

board mechanical connection at end of stave. • And related bonding of cable into stave. How to co-

cure (if want to use this to reduce mass)

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Plan

• Highly funding dependent, uncertain• Priorities– Assemble “electrical staves” with working cables,

LBNL and Bonn. Get experience.– One of these at least using co-curing, minimal

material techniques developed via short prototypes

– I-beam with cabling, mechanical concept, not electrical