glast lat silicon tracker marcus zieglerieee 2005 1 the silicon tracker readout electronics of the...
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GLAST LAT Silicon Tracker
Marcus Ziegler IEEE 2005 1
The Silicon Tracker Readout The Silicon Tracker Readout Electronics of the Gamma-ray Electronics of the Gamma-ray Large Area Space TelescopeLarge Area Space Telescope
Marcus Ziegler
Santa Cruz Institute for Particle PhysicsUniversity of California at Santa Cruz
GLAST LAT Collaboration
Gamma-ray Large Gamma-ray Large Area Space Area Space TelescopeTelescope
GLAST LAT Silicon Tracker
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GLAST LAT Tracker OverviewGLAST LAT Tracker Overview
e+ e–
Si Tracker880 000 chanels160 Watts
The LAT Tracker is devided into:
-16 Tracker Towers
each stack is composed out of 19 trays
Tray:
Carbon-composite panel with Si-strip detectors on both sides.
On the bottom side is a tungsten foil bonded
GLAST LAT Silicon Tracker
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TowerTower
GLAST LAT Silicon Tracker
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Electronics PackagingElectronics Packaging
Kapton readout cables.
Tested SSDs procured from Hamamatsu Photonics
19 “trays” stack to form one of 16 Tracker modules.
Electronics and SSDs assembled on composite panels.
4 SSDs bonded in series.
Composite panels, with tungsten foils bonded to the bottom face.
2592
10,368
342
64834218
Carbon composite side panels
Chip-on-board readout electronics modules.
Electronics mount on the tray edges.
“Tray”
GLAST LAT Silicon Tracker
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Detail of an EM MCM, at One EndDetail of an EM MCM, at One End
Nanonics Connector(will be Omnetics)
Pitch-adapter flex circuit90° radius
GTRC ASIC
GTFE ASIC
PolyswitchGrounding screw hole
Shown prior to wire-bond encapsulation and conformal coating.
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Readout ElectronicsReadout Electronics
GTFE GTFE GTFE GTFE GTFE GTFE
GTRC
GTFE GTFE GTFE GTFE GTFE GTFE
GTRC
GTFE GTFE GTFE GTFE GTFE GTFE
GTRC GTRC
GTRC
GTRC
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Electronics PackagingElectronics Packaging
Dead area within the tracking volume must be minimized.
Hence the 16 modules must be closely packed.
This is achieved by attaching the electronics to the tray sides.
Flex circuits with 1552 fine traces are bonded to a radius on the PWB to interconnect the detectors and electronics.
Detector signals, 100 V bias, and ground reference are brought around the 90° corner by a Kapton circuit bonded to the PWB.
Composite Panel
High thermal conductivity transfer adhesive
PWB attached by screws
Detector
Readout IC
Machined corner radius with bonded flex circuit.
GLAST LAT Silicon Tracker
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Mechanical StructureMechanical Structure Carbon-fiber composite used for radiation transparency,
stiffness, thermal stability, and thermal conductivity. Honeycomb panels made from machined carbon-carbon
closeouts, graphite/cyanate-ester face sheets, and aluminum cores.
High-performance graphite/cyanate-ester sidewalls carry the electronics heat to the base of the module.
Titanium flexure mounts allow differential thermal expansion between the aluminum base grid and the carbon-fiber tracker.
SSDs Bias Circuits
Tungsten
Panel
MCMFlexure MountsThermal Gasket
Bottom Tray
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ConclusionsConclusions
Solid-state detector technology and modern electronics enable us to improve on the previous generation gamma-ray telescope by well more than an order of magnitude in sensitivity.
The LAT tracker design uses well-established detector technology but has solved a number of engineering problems related to putting a 900,000 channel silicon-strip system in orbit: Highly reliable SSD design for mass production Very low power fault-tolerant electronics readout Rigid, low-mass structure with passive cooling Compact electronics packaging with minimal dead area
We have validated the design concepts with several prototype cycles and are now approaching the manufacturing stage.
We’re looking forward to a 2007 launch and a decade of exciting GLAST science!