SLHC Pixel Layout Studies

S. Dardin, M. Garcia-Sciveres, M. Gilchriese, N. Hartman

LBNLNovember 4, 2008

Background and Goals

• Studies shown here are simple, almost “lines on paper”

• Have included some realism in lengths of staves and radial extent of disks based on module dimensions but don’t believe dimensions to the mm-level

• Previous reports are worth looking at to understand evolution – see for example talks here

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Assumptions

• Minimum of four pixel hits• Cover || ≤ 2.5 for tracks |z| ≤ 10 cm (nominally

2 although needs to be confirmed as design of SLHC evolves)

• Define “pixel-only volume” bounded by (short) strip detectors (R ≤ about 35 cm but final boundary TBD) and beam pipe at inner radius

• Two pixel hits permanent• Two hits insertable from end/replaceable

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June 2008 Layout 1

Radi

us(c

m)

Z(cm)

Insertable sectionSingle-sided staves here

Fixed section

“End-of-stave card”Arbitrary guess

Insertion tube

Boundary of silicon strip trackerDrawn width represents tiltModules both sides assumed here

AngleCommon support shell “End-of-disk card”

Not shown

June 2008 Layout 2• “Bent” stave to reduce material• Measurement mostly at larger R• Gap in coverage and bend?

Input to Project Office Models

Many Options Explored

• These and more are described more here.

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Monolithic insertable pixel optionsMonolithic insertable pixel options

BOX Section Beam, single cooling circuit.

I Section Beam, single cooling circuit.

Buttable modules to avoid large gaps

Pixel Barrel Overall - ExamplePixel Barrel Overall - Example

Layer Number Staves Modules per Stave Total Modules Module Type0 15 32 480 Single Chip1 15 28 420 4Chip Active Edge2 32 32 1024 4Chip Normal3 40 32 1280 4Chip Normal

Disk Examples

• Hermetic by design (see local supports talk for how implemented)

• Overlaps in R and

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Both sides One side

Push Outer Envelope• What is outer envelope?• Maintain space for support structure and

services at outer radius. • This is tight if outer envelope is about 34cm,

based on current experience

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Disk 1 ave Z 79.685 cmDisk 2 ave Z 94.9 cmDisk 3 ave Z 109.264 cm

Disk 1 OD 28 cmDisk 1 ID 12.1 cm

Disk 2 OD 28 cmDisk 2 ID 12.1 cm

Disk 3 OD 20.1 cmDisk 3 ID 16.05 cm

Barrel ave R Z of active length in cm Z 1/2 active length in cm

3.7 cm 64.8 32.4007.5 cm 113.4 56.70016 cm 117.032 58.51620 cm 119.55 59.775

Support tube ave R10.5 cm

OD limit R33.85 cm

End-of-disk “cards”Same arbitrary area/moduleas for staves

More Outside Room

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• Reduce radius of outer layers by 2 cm• Reduce disk size• May allow exterior support structure and

services routing or support from insertion tube and routing along it.

Disk 1 ave Z 83.97 cmDisk 2 ave Z 99.55 cmDisk 3 ave Z 110 cm

Disk 1 OD 26.75 cmDisk 1 ID 14.8 cm

Disk 2 OD 26.75 cmDisk 2 ID 14.8 cm

Disk 3 OD 20.58 cmDisk 3 ID 16.53 cm

Barrel ave R Z of active length in cm Z 1/2 active length in cm

3.7 cm 64.8 32.4007.5 cm 113.4 56.70014 cm 117.032 58.51618 cm 119.55 59.775

Support tube ave R11 cm

OD limit R33.85 cm

More Forward Hits• Possible to add more forward hits• Could keep all disks same and do this(not

shown here but easy to imagine)• Of course could add disk also….

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Disk 1 ave Z 84 cmDisk 2 ave Z 100 cmDisk 3 ave Z 110 cm

Disk 1 OD 26.75 cmDisk 1 ID 14.8 cm

Disk 2 OD 26.75 cmDisk 2 ID 14.8 cm

Disk 3 OD 22.8 cmDisk 3 ID 14.8 cm

Barrel ave R Z of active length in cm Z 1/2 active length in cm

3.7 cm 64.8 32.4007.5 cm 113.4 56.70014 cm 117.032 58.51618 cm 119.55 59.775

Support tube ave R11 cm

OD limit R33.85 cm

My Comments• Staves are long(material?) and disks are big. Need reality check from

design and prototypes before expending too much effort on detailed layouts.

• Nearing end of utility of simple layout studies (at least for engineering)• Obvious information needs

– What is outer envelope of pixels?– What are the dimensions of end-of-stave and end-of-disk cards?– Insertion tube (only) or insertion+support outer layers? Stiffness and other

requirements (it’s not so large in diameter)– Thermal requirements for this tube– Feedback from services and support envelopes => change layout

• Time for some more detailed modeling with real engineering design input.

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