HFT PXL MechanicalWBS 1.2

March 2010Howard Wieman LBNL

1

Topics - PXL (WBS 1.2)

• PXL reminder• Installation steps• design and tooling

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 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

5

HFT PXL – insertion design

6

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

7

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

8

9

HFT PXL – installation design

HFT PXL – installation design

10

remove box rails

slide detector home

remove box and connect services

detector insertion

11

12

Vacuum chuck for probe station

13

14

15

maneuvering the detector into the IP with cams and rails

PIT

PST

16

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

17

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)

18

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

19

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

20

21

apply glue and mount to rails with post passing through holesinsert rails with rail holder fixture

Bond rail supports

bonded rail support

22

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

23

PIT with rails attached

rail tester

24rail_test_system.SLDASM (operation view)

tester rail attachment

• Assemble PIT flange mounting plates• Assemble tester frame

25

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

26

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.

27

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

28

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

29

PST kinematic mount attachment

30

•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

31

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

adhesive

PST kinematic mount attachment

32

• 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

33

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.

34

Coordinate Measuring Machine (CMM) configuration

35

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

36

37

38

39