HFT PIXEL Mechanical Progress
Strasbourg
June-2009
Wieman
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Topics
• Thin support beam• ladder fabrication• Air cooling analysis• Air vibration tests• Full scale cooling
tests• Spatial mapping
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Development of sector beam and ladder fabrication
• Eric Anderssen and Tom Johnson have been working on fabrication methods for:– Sector Beam– and Ladders
• Produced sample beams, 244 m thick, 7 ply, 21 gm
• expected ladder mass 7.5 gm
ladders
sector beam
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prototype design being built
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PIXEL mass breakdown
Sector structures
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ladder fabrication and tooling
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ladder fabrication and tooling
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ladder fabrication and tooling
9finalizing mechanical designs and developing rapid production methods
ladder fabrication and tooling
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ladder withsilicon heaterchips(50 m thick)
wire bonding 50 m silicon to flex PC
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vacuum chuck tosecure flex and siliconflat against solid surfaceto remove bounce
Any bounce then no bond
Good Newsafter a couple of minor modifications to the vacuum chuck wire bonding works well
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ladder to sector bond fixture
ladder to out2 bond fixture.SLDASM
(designed to allow ladder replacement)
ladder to sector tooling fixtures (4 stations)
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Air cooling of silicon detectors – Computational Fluid Dynamics (CFD) analysis
air flow path – flows along both inside and outside surface of the sector
• Silicon power: 100 mW/cm2 (~ power of sunlight)
• 240 W total Si + drivers
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Air cooling – CFD analysis• air flow velocity 9-10 m/s• maximum temperature rise
above ambient: 12 deg C• sector beam surface –
important component to cooling
• dynamic pressure force 1.7 times gravity
stream lines with velocity
silicon surface temperature
velocity contours
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430 mm ID
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vibration modes – preliminary – better composite numbers available
229 Hz
316 Hz
224 Hz
473 Hz
348 Hz
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vibration modes with reinforced end cap
• The message– Lots of complicated modes close in
frequency– End cap raises frequencies a bit
259 Hz
397 Hz
276 Hz
441 Hz
497 Hz
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air velocity probetwo positions shown
capacitance vibration probetwo positions shown
carbon fiber sector beam
wind tunnel setup to test vibration and displacement
adjustablewall for airturn around
air in
air out
C:\Documents and Settings\Howard Wieman\My Documents\aps project\mechanical\PXL phase 1 sept 2008\sector ph1 wind tunnel.SLDASM
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wind tunnel, rapid prototype parts from model air flow control
parts built with3D printer
parts built with SLA, stereolithography apparatus
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wind tunnel
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capacitive probe vibration measurements
air velocity 2.7 m/s
position signal, 25 m/volt
air velocity 9.5 m/s
position signal, 25 m/volt
log FFT, peak at 135 Hz
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Ladder vibration induced by cooling air
30m
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20m
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system resolution limitall errors
desired vibration target
required air velocity18 mph
0 2 4 6 8 10 120
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measured vibration with negative pressure modemeasured vibration with positive pressure mode
Ladder Vibration
air velocity (m/s)
vibr
atio
n R
MS
(m
icro
ns)
5.77
8.66
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Full sized cooling tests
Thermal camera window not shown
> 300 CFPM air flow for verification of cooling capability
Cooling tests will begin as soon as prototype sectors completed
9 inch diameter tube mocks upMSC
23dust collector for air supply
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development of spatial map procedureBob ConnorsSpiros MargetisYifei Zhang
touch probe 2-3 m (xyz) andvisual 2-3 m (xy) 50 m (z)
active volume: huge
10 gm touchprobe force(could deflect beam)
MEMOSTAR3, 30 m pitch
We need better fiducialson the main pad side that the coordinate machine can find automatically.
The pads will be buried and not visible
Recommended
