ILC Vertex Tracker Ladder Studies At LBNL M Battaglia, D Contarato, L Greiner, D Shuman LBNL,...
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Transcript of ILC Vertex Tracker Ladder Studies At LBNL M Battaglia, D Contarato, L Greiner, D Shuman LBNL,...
ILC Vertex Tracker Ladder StudiesAt LBNL
M Battaglia, D Contarato, L Greiner, D ShumanLBNL, Berkeley
Mechanical Test Facilities at LBNLMechanical Test Facilities at LBNL
Lucite wind tunnel Thin silicon ladder,
tension support
Laser light source
Camera
● Environmental chamber (down to -70ºC) for characterization of temperature cycling and humidity effects on prototype ladders
● High resolution IR camera for studying temperature gradient of prototype ladders
● Facility for studies of cooling and mechanical stability with nitrogen and air flow, equipped with a laser holography system for real time measurement of distortions in prototype structures with sub-µm resolution
● Capacitive probe system with sub-µm resolution; study displacements and vibrations induced by air cooling or other forces
● Composite materials lab for fabrication of light structures
VTX Ladder Design & TestingVTX Ladder Design & Testing
• LCRD funding supports new program of engineering design, construction and characterization of full ladder equipped with back-thinned CMOS pixel sensors in collaboration with STAR HFT project
0.282% X0
• STAR low mass carrier: 50m CFC+3.2mm RVC+50m CFC (=0.11%X0)
0.282Total
0.11CF / RVC carrier
0.0143Adhesive
0.090Cable assembly
0.0143Adhesive
0.0534MIMOSA detector
% radiation lengthComponent
VTX Ladder Design & TestingVTX Ladder Design & Testing
X
Y
Z
2-15 2-20 2-26 2-29 2-30 2-32 2-27 2-1
X
Y
Z
2-15 2-20 2-26 2-29 2-30 2-32 2-27 2-1
STAR study of accuracy of chip positioning on carrier:50 m back-thinned MIMOSA5 are positioned using a vacuum chuck with alignment bump edge and individual vacuum chuck valves
20.32
20.33
20.34
20.35
20.36
20.37
20.38
0 50 100 150
MIMOSA5 corner locationson prototype ladder
bottom corner Ytop corner Y
Y
X
Profile of Chip Elevation on CarrierChip Corner Locations
Flat to ~ 30 m
Accurate to~ 20 m
Measurementsusing OpticalSurvey Machinewith ~ 1 m accuracy.
VTX Ladder Design & TestingVTX Ladder Design & Testing
IR Camera ImageAir Cooling Test
Thin Chips Heating cable
(80mW/cm2)
T(0C)
0
2000
4000
6000
8000
1 104
1.2 104
1.4 104
27 27.5 28 28.5 29
10 deg air = 0 m/s
Cou
nt
microns
Std Deviation = 0.15662692
0
1000
2000
3000
4000
5000
6000
7000
13 15 17 19 21 23 25 27
10 deg air = 1.0 m/s
Cou
nt
microns
Std Deviation = 1.575661SD=0.16 µm SD=1.6 µm
Air=0 m/s Air=1 m/s
• Vibration from air cooling measured with capacitive probe; location distribution with SD~1 m at 1.0 m/s airflow on unsupported end of ladder
• Mechanical and thermal characterization of STAR prototype, study of heat removal using low-speed airflow
Thin CMOS Pixel StudiesThin CMOS Pixel Studies
• Back-thinning of diced chips using grinding process by Aptek Industries• Thinned over 15 MIMOSA5 chips, process reliable down to 40 m, yield of functional chips~90%• Measured chips thickness:
FEA stress analysis offlattened 50 m chip
Surface map of 50 m chip(measured)
“40 m”
“50 m”
Before (550±0.5) m
(50±7) m
(41±6) m
VTX Ladder Design & TestingVTX Ladder Design & Testing
• FEA of prototype structures (core-cooled Si/CF/RVC sandwich, Si/Al/RVC sandwich, CVD coated CF) in progress using data from surveys of 40 and 50 m thin chips, first results promising, test of prototype in 2008
Low density (0.2-0.6g/cc)High thermal conductivity (40-180W/m K) carbon foam
Concept forSymmetric LadderSandwich Support with Air Coolingthrough Core
Ladder side view