PHENIX FVTX

Status of Mechanical and Thermal Design Work

Eric Ponslet, Shahriar Setoodeh, Roger SmithHYTEC Inc.

Los Alamos, NMMay 2, 2007

HPS-111006-0011 – FVTX Mechanical/Thermal Design – May 2, 2007 – Slide 2

Final Design Package• Final Report and Drawing Package

– Documents the Preliminary Design of FVTX structures and cooling system– delivered to LANL on 04/24/07– Available on Twiki at http://pvd.chm.bnl.gov/twiki/bin/view/VTX/FVTXDesignReports

Report: HTN-111006-0003Drawings: 111-PHX-01-3000 to -3012

HPS-111006-0011 – FVTX Mechanical/Thermal Design – May 2, 2007 – Slide 3

Latest Baseline Design• Change since last status presentation (UNM, March 12, 2007)

– Modules staggered in Z to provide sufficient space on HDI for FPHX chips, wire bonding pads, and decoupling capacitors

• Modular Design– Sensor module (“wedge”) Half Station Half Cage FVTX

• Wedge built on a Graphite Fiber/Cyanate Ester Thermal Backplane– Serves as structural support and heat transfer path to edge cooling– 0.76mm thick K13CU/CyE

• Very high thermal conductivity fiber

• Wedges are Fastened to Support Panel– Two alignment pins (ceramic/glass?) and 3 screws (nylon) per wedge– RT-cured silicone bridge provides thermal interface to cooled support panel– Allows replacement of single defective wedge

• BUT: requires cutting the Silicone thermal bridge

• Half-Disk Support Panel and Support Cage– Sandwich construction: Graphite fiber (M55J) faces and aluminum honeycomb

• Liquid Cooling– Tube embedded in support panel in place of core, near OD of half disk– Single phase coolant at high flow rate (turbulent)

HPS-111006-0011 – FVTX Mechanical/Thermal Design – May 2, 2007 – Slide 4

• Two variations: upstream and downstream– HDI tail folded forward or backward

Sensor Module

Backplane (0.76mm graphite fiber composite)

Screw (nylon)

Pin hole(for alignment)

Pin hole(for alignment)

HDI

Connectors for extension cables

Detector

FPHX Chips

Screw (nylon)

(All bonds use rigid epoxies)

HDI

Sensor

FPHX chips

Backplane

Rigid, thermally conductive epoxy

Rigid epoxy

HPS-111006-0011 – FVTX Mechanical/Thermal Design – May 2, 2007 – Slide 5

Half-Station Sub-Assembly

Conductive silicone bond(for heat transfer)

HDI

Sensor

FPHX chip

Screw

Pin

Support Tab

Support Tab

Support Panel

Support Tab

Low-mounted module

High-mounted module

Not enough space if

modules side by side

HPS-111006-0011 – FVTX Mechanical/Thermal Design – May 2, 2007 – Slide 6

Cooling and Support Tab Detail

Screw hole (mounting to cage)

Pin (alignment to cage)

Hose barb for coolant(back side)

Screw (holds wedge on disk)

Silicon detectors, HDIs, and back-planes made transparent for clarity

Pin (aligns wedge on disk)FPHX chip

Built-in cooling tube

Silicone heat transfer interface(RT-cured, conductive silicone)

Sensor

CC (TBC) heat transfer bridge

HPS-111006-0011 – FVTX Mechanical/Thermal Design – May 2, 2007 – Slide 7

Support Panel Construction

Locating pinInsert for pin (TBD plastic)

Insert for screw (TBD plastic)

GFRP Face sheet (0.25mm)

Honeycomb core (4.76mm, 32 kg/m3)

Foam core(TBD mat’l)

Core insert for pins and screws (TBD plastic)

Cooling tube

Hose barb

GFRP Face sheet (0.25mm)

Standoff plate (TBD Plastic)

Mounting tab

HPS-111006-0011 – FVTX Mechanical/Thermal Design – May 2, 2007 – Slide 8

Half Cage Sub-Assembly

Cooling hose (silicone)

Sta

tion 1

Sta

tion 2

Sta

tion 3

Sta

tion 4

Z

Y

HPS-111006-0011 – FVTX Mechanical/Thermal Design – May 2, 2007 – Slide 9

FVTX–VTX Interference / Space Allocation

VTX Strip Layer (#4)

VTX Strip Layer (#3)

VTX Pixel Layer (#2)

VTX Pixel Layer (#1)

Interference!(Wrap FVTX cage behind station 1

Reduce radius of station 1Possibly move VTX4 out 1cm)

FVTX

Sta

tion 1

FVTX

Sta

tion 2

FVTX

Sta

tion 3

FVTX

Sta

tion 4

HPS-111006-0011 – FVTX Mechanical/Thermal Design – May 2, 2007 – Slide 10

Radiation Length Status (1/2)• Total RL of Station 2, 3, or 4 (normal incidence)

– Area averaged to active area (45mm IR, 170mm OR) = 2.41%

Distribution of area-averaged, normal incidence RL

0.000%

0.100%

0.200%

0.300%

0.400%

0.500%

0.600%

0.700%

RL%

Total = 2.41%

HPS-111006-0011 – FVTX Mechanical/Thermal Design – May 2, 2007 – Slide 11

Radiation Length Status (2/2)• Local RL of Station 2, 3, or 4 (normal incidence)

– Local extremes range from 1.8% to 9.1%

6.6

7.3

4.8

5.4

6.69.1

4.4

1.82.2

2.3

5.03.93.9

4.4

1.8

2.2

Local values of %RL at normal incidence

HPS-111006-0011 – FVTX Mechanical/Thermal Design – May 2, 2007 – Slide 12

Cooling System• Keep FVTX near Room Temperature

– Gas enclosure also at room temperature

• Power Dissipation– 8W per half disk (stations #2, 3, 4)

• Cooling Tube Embedded in 3/16” Support Panel– Square cross section (3/16” by 3/16”) with super-thin (<50μm) nickel wall– Vendor currently under contract for trial fabrication of tube (~ 4 weeks)

• Coolant– 3M Novec HFE-7000– Completely harmless to (even live) micro-electronics– Environmentally friendly– Dense (1.4 × water)

• Flow Regime– Single phase– Strongly turbulent

• Re ~ 10,000• Flow velocity ~ 0.7 m/sec• Flow rate ~ 20 g/sec = 14 gallons/hour (per ½ cage)

– Flow-induced vibrations?• Need testing

HPS-111006-0011 – FVTX Mechanical/Thermal Design – May 2, 2007 – Slide 13

Wedge Analysis

Temperature Contour

Max Tº = 19.3ºCWarmest FPHX

Min Tº = 15ºC (Boundary condition at back side of backplane)

Tem

pera

ture

(°C

)

• Warmest FPHX is 4.3ºC Warmer than Back Edge of Backplane– 9.3ºC warmer than coolant

• Thermal stresses are very low– Rigid adhesives are fine

Cooling-induced Distortions(assembled at room temperature)

Deflect

ion (

m)

Max deflection 8.1μm

HPS-111006-0011 – FVTX Mechanical/Thermal Design – May 2, 2007 – Slide 14

Coolant to ROC Thermal Path• 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

HPS-111006-0011 – FVTX Mechanical/Thermal Design – May 2, 2007 – Slide 15

Liquid Cooling Circuit• Run 4 Half-disks in Series

5psi, 10°C (inlet)

Warmest FPHX chips: ~19.3°C (station 4)

4.6psi, 10.3°C

3.3psi, 11.1°C (outlet)

4.2psi, 10.6°C

3.7psi, 10.9°C

Warmest FPHX chips: ~19.6°C (station 3)

Warmest FPHX chips: ~20.0°C (station 2)

HPS-111006-0011 – FVTX Mechanical/Thermal Design – May 2, 2007 – Slide 16

Station- and Cage-Level Modeling

Fundamental Vibration ModeDistortion due to Cooling(assembled at room temperature)

Max deflection ~ 21μmMax deflection within active area ~ 8μm

138Hz

HPS-111006-0011 – FVTX Mechanical/Thermal Design – May 2, 2007 – Slide 17

Conclusions• We have a fairly detailed preliminary design

– But not a final design; detailing and some material selections pending

• Meets key requirements– Dimensional stability– Stiffness– RL

• Some remaining questions and issues– See next slides

• More work needed before fabrication phase– See next slides for details– Evolve design (following VTX and system-level evolution)– Resolve pending design issues– Prototype & Test

• Our FVTX design contract is now closed– No FVTX funding at this time

• Funding request in place with BNL for R&D funding– Cover minimal manpower level & prototypes through end of CY– What are our chances of getting funded? When?

HPS-111006-0011 – FVTX Mechanical/Thermal Design – May 2, 2007 – Slide 18

Remaining Technical Issues• Flow-induced vibrations:

– Must insure that vibration level from turbulent flow is low• Requires testing

• Support and cooling of sensor modules at edges of stations– Sensor modules at separation plane (6 and 12 o’clock) are insufficiently cooled and

could use better mechanical support

• HDI tails tool long for Station 4– Little space available downstream of station 4, within space allocation– Requires tight bend radius– Connectors/backing plate are in the way

• VTX/FVTX Interference– Solutions have been identified– Will be implemented as soon as funding is available

HPS-111006-0011 – FVTX Mechanical/Thermal Design – May 2, 2007 – Slide 19

Future Work: Before Construction Phase• Short-term (before construction phase)

– System Design (shared with / largely funded by VTX)• Gas enclosure• “Big wheel”• Routing and support of utilities• Initial alignment / surveying approach• Other

– Effect of radiation on coolant (exposure tests)– Effect of coolant on materials (exposure tests)

– Continue evolving FVTX design– Prototyping

• See next slide

• Construction phase– Grounding– Final material selections– Detailed design and fabrication drawings

HPS-111006-0011 – FVTX Mechanical/Thermal Design – May 2, 2007 – Slide 20

Prototyping• Main focus of R&D funding request• Sensor module prototypes

– GFRP backplanes + dummy HDI + dummy sensor + resistive heaters– Used to

• Test assembly tooling• Thermal cycling (stresses in bonds and SSD)• Heat transfer testing • Validate temperature induced deflections (TV Holography?) – insufficient funding

• Half-Station prototype– One half disk (large)

• Supported by dummy structure (no cage)• Populated with dummy detector modules

– Used to• Test manufacturing, assembly, and alignment concepts• Measure flow induced vibration• Heat transfer tests

• Half-cage prototype– Experiment with manufacturing approach– Double-duty as iFVTX support cage

HPS-111006-0011 – FVTX Mechanical/Thermal Design – May 2, 2007 – Slide 21

Program Management Transition• Eric Ponslet is leaving HYTEC

– Effective May 17– Personal reasons: going climbing…

• RJ Ponchione taking over PM role for PHENIX activities at HYTEC– Outstanding design engineer & quick learner– Rest of team remains unchanged:

• Shahriar Setoodeh: analytical design and simulation• Vince Stephens: composite material expertise, PM assistance• Roger Smith: CAD modeling and packaging

• Transition phase in progress– Immediate priority is VTX (stave prototypes)– iFVTX work continues as required– No FVTX funding at this point