walter sondheim, fvtx review nov 12 th,2008 1 fvtx mechanical status : walter sondheim - lanl...
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Walter Sondheim, FVTX Review Nov 12th,2008 1
FVTX Mechanical Status:
Walter Sondheim - LANL Mechanical Project Engineer; VTX &
FVTX
Walter Sondheim, FVTX Review Nov 12th,2008 2
Mechanical Design Philosophy:
• The Design of the FVTX structures and services have been driven by the following requirements;– High mechanical and thermal stability. – Radiation tolerance up to an integrated dose over 10
years of 300 – 500 krads in the region of the detectors and 200 krads in the region of the ROC (read-out-card).
– High transparency to particles, keep the radiation length to a minimum, especially the material mass that is in the acceptance.
– Silicon modules to be maintained at room temperature or slightly lower, sensor electronics has low susceptibility to radiation damage.
– Very low maintenance over 10 year expected lifetime.– High granularity of the services to increase the reliability
of the operation.– Modular Assembly.
Walter Sondheim, FVTX Review Nov 12th,2008 3
VTX-FVTX Half Assembly for Introduction:
Two half FVTX detectors
Beryllium beam-pipe, 41.021 mm OD X 800.0 mm long
VTX detector, 4 layers; inner 2 pixels, outer two strip-pixel sensors
Big Wheel region; read-out electronics for VTX&FVTX
Support structure and isolation mounts attached to central magnet
Walter Sondheim, FVTX Review Nov 12th,2008 4
Sensor Module: Two variations for stations2 & 3, upstream and downstream:
Upstream Downstream
POCO graphite support block with pin hole for alignment, screw hole for mounting
PEEK support block with pin hole for alignment and screw hole for mounting
Graphite back-plane 1.56 mm, K13C2U carbon fiber, Cyanate Ester resin, fabrication at LBNL
HDI .44 mmSensor
.32 mm
FPHX chips bonded to HDI
Mounting screw location
Mounting screw location
HDI connectors to extension cable to ROC
Bonding of FPHX chips to HDI use Arclad 8026 transfer adhesive, 1 mil
Bonding of silicon sensor to carbon backplane Arclad 8026 and Tra-bond 2902 silver epoxy
Walter Sondheim, FVTX Review Nov 12th,2008 5
Half-Station sub-assembly, stations 2, 3 or 4:
Mounting and alignment pins in tabs, 3 per station half disk
Thermally conductive block to transfer heat from wedge to support panel
Nylon mounting screw – (phillips head)
Graphite faced support panel
Four layers of 15 degree wedges, 2 layers on each side of support panel
Each wedge staggered in Z, 15 degrees between wedges on one side, upstream to downstream sides of panel offset by 7.5 degrees – hermetic in phi. Each silicon sensor covers 7.5 degrees in phi.
Walter Sondheim, FVTX Review Nov 12th,2008 6
Support Panel Construction:
Hose barb PEEK
Insert for screws and pins - PEEK
Wedge locating pin
Mounting tab
GFRP face sheet, .25 mmCore – foam, 4.76 mm
Core insert, pins and screws, PEEK
Cooling channel, PEEK
GFRP face sheet, .25 mm
Fabrication of disk assembly will take place at LBNL composite shop
Holes for survey flag along edge
Walter Sondheim, FVTX Review Nov 12th,2008 7
Half Cage Assembly with Liquid Cooling Circuit:
Each station is cooled in parallel with the other stations.
Inlet temperature 0 – 10 degrees C, delivery pressure 5 psi
Delta-T per ½ station 1.8 degrees C, delta p .4 psi
Coolant 3M Novec 7200
Inlets
Outlets
Novec 7200:
Boiling point 76 degree C
Melting point -138 degree C
Vapor pressure 109 mmHg @ 25 degrees C
Neutron irradiation study at LANL’s WNR facility – total dose 6.7 X 10**11 n/cm**2, nominal energy 800 Mev. Samples were sent to 3M for analysis of free Flouride, no indication of significant degredation.
Walter Sondheim, FVTX Review Nov 12th,2008 8
FVTX Cage:
Cage design uses CN60 carbon fabric with a EX1515 resin. FEA analysis indicates very rigid structure < 25. microns.
Blocks and flanges POCO graphite ACF-100Q.
Note: the mounting blocks for the 4 stations will be clocked in 1 degree increments.
Each FVTX interfaces directly with the VTX space-frame.
For scale: 400. mm in diameter, 187. mm in length.
Penetrations in shell for survey/alignment flags
Fabrication will take place at LBNL composite shop.
Walter Sondheim, FVTX Review Nov 12th,2008 9
Coolant to FPHX Chips Thermal Path – 2007 review – current changes:
• Use Simple Correlations to Evaluate– Pressure drops
– Temperature drop from fluid to cooling tube
Approximate temperatures with 10°C coolant flowing at Re~10,000(0.76mm K13CU backplane, 50μm Nickel tube, 0.2 W/mK epoxy, 0.75 W/mK silicone)
Inside of F.S: 11.7°C
Top of thermal bridge: 12.5°C
Warmest FPHX: 19.3°C
Tube wall: 11.6°C
HDI
Panel core (Al HC)
Bulk coolant: 10°C
Back of wedge backplane: 15°C
Inn
er
Radiu
s
FoamThermally Conductive Epoxy
Thermally Conductive Silicone
Outside of F.S: 12.2°C
Oute
r R
adiu
s
Bottom of thermal bridge: 12.3°C
Backplane
Cooling tube
Thermal bridge
Thermally conductive silicone
Thermally Conductive Epoxy
2008 Changes to Wedge:
FPHX readout chip power increased 100 to 600 micro-watts per chip.
Rerun thermal model and FEA analysis over next month
Thicker 2X
Thicker 2.5X
Channel
POCO graphite
Arclad 8026 transfer adhesiveFoam
PEEK
Walter Sondheim, FVTX Review Nov 12th,2008 10
Large Station and Cage-Level Modeling:
Fundamental Vibration ModeDistortion due to Cooling(assembled at room temperature)
Max deflection ~ 21μmMax deflection within active area ~ 8μm
138Hz
Walter Sondheim, FVTX Review Nov 12th,2008 11
Measurement of Central magnet vibration;
•Vibration Level Threshold 1*E-8 g2/Hz•Accelerometer Noise Floor 1*E-11 g2/Hz•Peak Measured Vibration 1.2*E-9 g2/Hz
• Vibration measurements were made on the Central magnet pole tips to see if mounting the VTX-FVTX vertex detectors off the pole tips would induce unwanted vibrations to the operation of this detector system.
• A comparison of the vibration levels measured and the threshold levels calculated – showed that the peak vibration levels are 10X lower than the threshold value.
• The measurements made in the PHEINX IR were successful at collecting sufficient data to conclude that the vibration levels on the support rails would not adversely affect the performance of the vertex detector system.
Walter Sondheim, FVTX Review Nov 12th,2008 12
Two Independent Halves:
“Big Wheel” cooling plate with coolant channel along perimeter, 3. mm Aluminum
ROC cards, 38. watts/card
Gas seal between layers
Wedge readout extension cables
This half FVTX assembly is stand alone, can be tested independently of the rest of the detector in a lab.
Walter Sondheim, FVTX Review Nov 12th,2008 13
Model heat transfer in lab:
• Model heat transfer in wedge assembly• Model heat transfer from ROC cards to cooling plate
Watlow heater 75 watt
Walter Sondheim, FVTX Review Nov 12th,2008 14
Summary: WBS 1.6 Mechanics – Schedule Dates & Manpower
• WBS 1.6 10/21/2005 – 9/29/2009– WBS 1.6.1 Specifications 10/21/2005 – 2/9/2006– WBS 1.6.2 Support Structure Cage 4/1/2007 –
12/25/2009– WBS 1.6.3 Wedge Backplane 4/11/2008 – 6/19/2009– WBS 1.6.4 Support Disk 1/4/2007 – 8/28/2009 – WBS 1.6.5 Alignment and Assembly 8/1/2008 – 3/5/2009
• Manpower– 1 engineers– 1 physicist liaison– HYTEC:
• 1 Engineer• 1 Designer