1 hft wieman 11/6/2004. 2 outline development status umimostar pixel detectors umimosa5...
DESCRIPTION
3TRANSCRIPT
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HFT
Wieman 11/6/2004
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Outline
Development Status MIMOSTAR pixel detectors MIMOSA5 Electronic Readout Ladder mechanics Beam pipe
Interface issues External tracking requirements Mechanical interface Calibration concept
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MIMOSTAR1 back from foundry
Prototype 128X128 30 m pixels (640X640 for the full size with 4 ms frame read time)
Final design features such as JTAG controlled internal biasing levels and multiple testing modes
Received chip from foundry in October 04, testing to start at LEPSI/IReS
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LEPSI/IReS MIMOSA V testing at LBNL
Developing readout skills at LBNL with a single MIMOSA V chip
MIMOSA V is an earlier device developed at LEPSI/IReS prior to the STAR work
Noise and leakage currents as previously measured by the Strasburg developers
Design in progress for a multi-chip ladder using the MIMOSA V
Leakage Current by Section
Bottom LeftTop LeftBottom RightTop Right0
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Section
Leak
age
Cur
rent
(fA
)
Leakage at 27 degCLeakage at 24.5 degCStrasbourg Leak (-5 degC)
Lara PierpointFabrice RetiereFred BieserRobin Gareus Howard MatisLeo Greiner
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Electronic/Mechanical Ladder Work – MIMOSA V
Multi chip design Readout with Off ladder ADCs Low mass mechanical development
0.010" Kapton cable
50 micron Si
0.004" carbon fiber
RVC0.004" carbon fiber
differential analog drivers/amplifiers
buffer
Carrier structure and cable are significantly wider for electronic performance test ladder.MIMOSA 5 MIMOSA 5
differential analog drivers/amplifiers
buffer
Top View
End View
Leo Greiner
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Ladder structure and X0 budget
Unidirectional carbon fiber skins separated by reticulated vitreous carbon (RVC) foam.
Very stiff Foam separation gives large
moment of inertia with little added mass
Carbon provides large Young’s modulus with low Z
With single end support expected to have < 10 m gravitational deflection
Ladder mass 2.7gm (a sheet of copier paper weighs 4.7 gm)
Carbon ladder structure 0.12% X0
Cable = 0.10%
50µm Si Detector = 0.053 %
Carrier (flat with RVC) = 0.12 %
Total for single ladder = 0.27%*
(500µm beam pipe = 0.142%)
*RDO chip will add another 0.053% if in final design.
More information on cable design/constraints at http://www.lbnl.leog.org/cable_constraints.htm
More information on material radiation length at http://www.lbnl.leog.org/pixel_rad_length.pdf
Leo Greiner
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Beam pipe concept required for HFT, discussions started with Brush Wellman
mm
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Beam pipe concept required for HFT, central region
Beam pipe supports attach here
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Ghost Tracks – pointing accuracy – hit density
Ghosts tracks, i.e. connecting the wrong hit to a track depends on Hit density on the tracking layer Track projection uncertainty to
the layer
P fs
s 1
Associate the closest hit to the track and the probability of a false association is:
where
s 2 2
Pfs
s 1
Eugene Yamamoto’s plot
This is not an efficiency – ghost trade off unless you set a limiting window
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Mechanical Interface
3 point kinematic connection to support structure
Two roll in rails
Kinematic structure concept to replace earlier arm design
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Alignment and spatial calibration procedure
Map all detector surfaces for each 4 ladder arm assembly with the vision coordinate machine
Assemble the 6 arm assemblies and map their relative positions
Install in STAR preserving all relative positions
If outside tracker alignment is fully known use a few tracks to determine the 6 parameters defining position of HFT within the outer tracker
If the outside tracker is not spatially calibrated do it with tracking through the HFT
BarBar vertex detector in the vision coordinate measuring machine
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Kinematic assembly – constrained to repeatedly assemble to same the same location
Allows assembly in vision coordinate machine to be the same as in the installed position
Ball in cylinder pair kinematic mounts
6 mount points used in assembly around beam pipe
3 mount points for each arm