Download - HFT PXL Mechanical WBS 1.2 March 2010
HFT PXL MechanicalWBS 1.2
March 2010Howard Wieman LBNL
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Topics - PXL (WBS 1.2)
• PXL reminder• Installation steps• design and tooling
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Pixel geometry. These inner two layers provide the projection precision
2.5 cm radius
8 cm radius
Inner layer
Outer layer
End view
One of two half cylinders
20 cm
coverage +-1
total 40 ladders3
Some pixel features and specifications
Pointing resolution (12 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 8 m rms
Position stability 6 m (20 m envelope)
Radiation thickness per layer
X/X0 = 0.37%
Number of pixels 436 M
Integration time (affects pileup) 0.2 ms
Radiation requirement
20 to 90 kRad 2*1011 to 1012 1MeV n eq/cm2
Rapid detector replacement
< 8 Hours
criticalanddifficult
more than a factor of 3 better than other vertex detectors (ATLAS, ALICE and PHENIX)
HFT PXL status – fabrication and tooling
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HFT PXL – insertion design
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insertion mechanism to guide detector around beam pipe and beam pipe support
uses track and carriage with hinge and cam to guide into final docking position
BBC reminder
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HFT PXL – installation design
• a well controlled method for installation of the pixel detector has been developed with emphasis on ease of operation and avoidance of detector risk
• The PXL assembly will be enclosed in a carrying box that is equipped for transfer of the detector assembly into the PXL support tube
• Once inserted on tracks the detector is guided into position locking kinematic mounts
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HFT PXL – installation design
HFT PXL – installation design
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remove box rails
slide detector home
remove box and connect services
detector insertion
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Vacuum chuck for probe station
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maneuvering the detector into the IP with cams and rails
PIT
PST
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MSCPixel Insertion TubePixel Support Tube
IDSEast Support CylinderOuter Support CylinderWest Support Cylinder
PIT
PST
ESC
OSC
WSC
Shrouds
Middle Support Cylinder
Inner Detector Support
Structures Exploded Detail
Assembly via bolted interfacesMSC installed into IDS after IDS assembled (detectors
not shown)IDS w/MSC installed into STAR
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Fixturing operations addressed:• PIT flange attachment• PIT rail attachment• Rail testing system• PST flange attachment• PST kinematic attachment• SSD locating fixture• Spatial mapping of the pixels with the Coordinate
Measuring Machine (CMM)
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PIT flange attachment
• assemble PIT end plate fixture• load flanges on PIT and insert into the PIT end plate
fixture• bond flanges (middle flange?)• cut holes for rail mounts • ready for rail mounting
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cut holes in PIT for rail supports
• install cutting guide, cut 4 holes• flip guide, cut 4 more• rotate PIT 180 deg, repeat for 8 more holes
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apply glue and mount to rails with post passing through holesinsert rails with rail holder fixture
Bond rail supports
bonded rail support
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remove post freeing rails and rail holder for removal
•remove rails and rail holder•release rails from rail holder•remove PIT from end fixtures (can’t remove with rails in place)•reattach rails to PIT with correctly identified posts
keep track of which post goes with which pad
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PIT with rails attached
rail tester
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tester rail attachment
• Assemble PIT flange mounting plates• Assemble tester frame
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install rail holder with rails, posts and bond pads removed
spread glue attach post andbond pad
cams are removed so that cross bars (not shown) coupling rails constrain the rotation angle in the guides
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remove posts
removing the posts allow that rails and rail holder to be removed.Rails without the rail holder can then be reattached to the rail tester by reinstalling the posts.
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attach kinematic mounts to rail testerbutch plate
grand master with kinematic mounts
cross arms
base plate attached to grand master
•remove rails•mount butch plate•apply glue to cross arms and base plate•attach grand master to butch plate•after glue sets remove butch plate and separate rail tester from PIT end plates•reattach rails•tester is now complete•grand master can be detached from base plate for later use after testing is complete
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PST flange attachment• Assemble PST end plate fixture• load flanges on PST and insert into the PST end plate fixture• bond flanges• cut holes (fixture yet to be designed)• Now ready for attaching the kinematic mounts
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PST kinematic mount attachment
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•remove east PST end plate•attach empty grand master to east PST end plate•attach PST end plate with grand master back on to the PST fixture
east PSTend plate
grand master
kinematic mount
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•assemble kinematic mounts with bond feet•attach mount with feet to cross bar•apply adhesive
adhesive
PST kinematic mount attachment
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• attach kinematic mounts to grand master by securing cross bar to grand master
• allow setup and remove cross bars from feet and grand master
• detach grand master from east PST end plate and support the grand master so that it does not load PST
• Remove end plates and grand master• PST done
Summary of PST kinematic attachment
• remove east PST end plate• attach empty grand master to east PST end plate• attach PST end plate with grand master back on to the PST fixture• assemble kinematic mounts with bond feet• attach mount with feet to cross bar• apply adhesive• attach kinematic mounts to grand master by securing cross bar to
grand master• allow setup and remove cross bars from feet and grand master• detach grand master from east PST end plate and support the
grand master so that it does not load PST• Remove end plates and grand master• PST done
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OSC fixture• The PIT fixture will also be used for the OSC since the OSC and PIT
are the same diameter. The base plate will be changed to set the correct length– fixture used for placing the OSC flanges– flats and reference groves used to position SSD supports. Up to 6 ladder supports
can be installed at one setting. The OSC is rotated in the fixture by 180 deg to do the remaining attachments.
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Coordinate Measuring Machine (CMM) configuration
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The grand master fixture is also used to support the detector halves in the CMM for doing the spatial map of the pixels. The fixture is supported in the CMM with 3 point support on the tooling balls for all the required angular positions. The relative mapping of all the tooling balls provides the required cross referencing of all the angular positions.
The same kinematic supports are used here as are used in the STAR detector installation.
backup
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