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PIXEL Mechanical

H. Wiemanface to face Integration15-May-2008

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topics

Introduction – mechanical design Pixel specifications and parameters Review insertion mechanics

Kinematic mounts air flow analysis

cooling air requirements

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Pixel geometry

2.5 cm radius

8 cm radius

Inner layer

Outer layer

End view

One of two half cylinders

20 cm

coverage +-1

total 40 ladders

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Some pixel features and specifications

Pointing resolution (13 19GeV/pc) m

Layers Layer 1 at 2.5 cm radiusLayer 2 at 8 cm radius

Pixel size 18.4 m X 18.4 m

Hit resolution 10 m rms

Position stability 6 m (20 m envelope)

Radiation thickness per layer

X/X0 = 0.28%

Number of pixels 436 M

Integration time (affects pileup) 0.2 ms

Radiation tolerance 300 kRad

Rapid installation and replacement to cover rad damage and other detector failure

Installation and reproducible positioning in a shift

criticalanddifficult

(ATLAS Pixels 1.2%)

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New details on kinematic mounts

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Pixel kinematic mounts

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Pixel kinematic mounts

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Pixel kinematic mounts

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Pixel kinematic mounts

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Pixel kinematic mounts

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preliminary air flow study

ANSYS CFX FEE Flow analysis simplified geometry to limit

mesh input velocity 8 m/s down

module support tube ISC blank off to force return

flow over silicon surfaces Result:

good flow velocity over both inner and outer silicon

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Pixel air cooling system

Internal duct 2 in diameter X 5 ft

Internal duct 2 in diameter X 5 ft

external duct 6 in diameter X 50 ft

external duct 6 in diameter X 50 ft

chiller

pump

Wide angle hall ISC

Air flow: 400 SCFM

Total pressure drop: 22 inches water

Temperature: 75 deg F/34 deg C or maybe -10 deg C

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Pixel heat load break down

Heat source Power (watts)

detector silicon 160

on ladder signal drivers 80

voltage regulators in ISC 24

heat influx through ducting and ISC if 35 deg C below ambient

600 - 2000

pumping 1000

Total load on chiller 1900 - 3300