HFT PXL Mechanical July 2010 Howard Wieman LBNL 1

Topics PXL reminder Tools for probe testing thinned 50  m chips PXL support with rapid detector swapping 2

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 ladders 3

Some pixel features and specifications Pointing resolution(12  19GeV/p  c)  m LayersLayer 1 at 2.5 cm radius Layer 2 at 8 cm radius Pixel size18.4  m X 18.4  m Hit resolution8  m rms Position stability6  m (20  m envelope) Radiation thickness per layer X/X 0 = 0.37% Number of pixels436 M Integration time (affects pileup) 0.2 ms Radiation requirement20 to 90 kRad 2* to MeV n eq/cm 2 Rapid detector replacement < 8 Hours critical and difficult more than a factor of 3 better than other vertex detectors (ATLAS, ALICE and PHENIX)

Thinned MAPS performance Thinner and smaller pixels than a hybrid pixel detector Accumulates statistics for 0.5 GeV D 0 36 times faster than a hybrid 200 times faster for 1.5 GeV 5

Mechanics Previously Reported Pointing requirements and a design to satisfy low multiple coulomb scattering plus high stability Detector assembly Vibration tests Cooling tests (Michal Szelezniak) 6

HFT PXL – fabrication and tooling 7

Vacuum chuck for probe station 8 handling of thinned silicon needed new mechanics for probe testing

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PXL support designed with emphasis on rapid replacement Motivation – most vertex detectors failed to produce because they could not be easily accessed and repaired Report on design progress on insertion and alignment – more involved mechanical design now practical with modern 3D CAD software that was not available for the original STAR design Designs guided by Eric Anderssen 11

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 12

maneuvering the detector into the IP with cams and rails PIT PST 13

14 initial open position clears the wide region of the beam pipe partially closed to fit into PST operating position closed around the beam pipe

15 top two kinematic mounts bottom not complete

16 hinge and carriage machined aluminum 2 mm thick contoured to form light rigid structures cam follower rail bearings cooling air hose adapter rapid prototype 1 mm thick carbon composite support tube and cooling air duct

17 testing of parts with CAD tools - work directly within CAD program 20 lb extended load for cables 0.4 mm displacement less than 10 minutes to setup problem with constraints and loads few seconds to mesh 12 seconds to solve

18 bending and breaking before building

19 system to test detector insertion with kinematic mounts

20 overlay of multi functional fixtures construct insertion test system bond flanges on carbon composite support tubes cut holes in support tubes bond rails into support tubes bond kinematic mounts into support tubes support detector in kinematic mounts for spatial mapping in coordinate measuring machine position SSD mounts on support tube for bonding

Coordinate Measuring Machine (CMM) configuration 21 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.

Status of parts Models and 60 pages of power point instructions submitted to LBNL main shop and University of Texas Austin machine shop – fabrication expected to start shortly 22

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 23

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 24

25 apply glue and mount to rails with post passing through holes insert rails with rail holder fixture Bond rail supports bonded rail support

26 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

27 PIT with rails attached

rail tester 28 rail_test_system.SLDASM (operation view)

tester rail attachment Assemble PIT flange mounting plates Assemble tester frame 29

install rail holder with rails, posts and bond pads removed spread glueattach post and bond pad cams are removed so that cross bars (not shown) coupling rails constrain the rotation angle in the guides 30

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. 31

attach kinematic mounts to rail tester butch 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 32

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 33

PST kinematic mount attachment 34 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 PST end plate grand master

kinematic mount 35 assemble kinematic mounts with bond feet attach mount with feet to cross bar apply adhesive adhesive

PST kinematic mount attachment 36 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 37

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. 38

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