November 16, 2001 C. Newsom BTeV Pixel Modeling, Prototyping and Testing C. Newsom University of Iowa

C. Newsom November 16, 2001

BTeV Pixel Modeling, Prototyping and

Testing

C. Newsom

University of Iowa


Overview

• Pixel Vessel & Internal support structures

• Vacuum Interface Board

• HDI/Flex Cable tests

• Pixel Support Module prototypes

• Materials testing

• Summary


Pixel Vessel and Internal Support Structures

• Rectangular Model-Integrated Carbon Manifold

• Carbon Fiber Half Barrel Structure


Rectangular ModelIntegrated Carbon Manifold

• The Pixel Support Modules mount directly on the carbon manifold

• Pure carbon joints are not sufficiently robust and need more research

• Manifold to Chip Module connections unsolved.


Carbon Fiber Half-Barrel Design• Barrel is double walled

laminated carbon fiber.• Cables are moved to a

side board.• Space at bottom now

available for motion, pump structures

• Insufficient space for HDI/daughter boards shown here.

• Major assembly problems


Vacuum Interface Board• Carry ~35,000 signals from inside to

outside the vacuum

• Constructed from 6 separate boards each with its own o-ring.

• Daughter cards have been removed to gain space.

• Ribbon cables pass through the surface and plug into the back side.

• Should we join the 6 boards, build a single board, …?


Vacuum Interface Board


HDI/Ribbon Cable Flexor

• One end is at -10C, and one at 25C to cool the power lines.

• Must absorb 2cm motion of half barrel during tuning.

• The cable must work in a vacuum.


Pixel Support Module Prototypes

• Fuzzy carbon prototypes– Initial Design– Improved Carbon Joints– Current Design

• Beryllium prototypes– Aluminum Modules (serpentine flow)– Aluminum Modules (parallel flow)– Stainless Steel Module (parallel flow)


Fuzzy Carbon Prototypes

• Thermal Prototype

• Mechanical Prototype

• Current Status


First Fuzzy Carbon Prototype

• Temperature drop of ~7 degrees (ok)• Mechanically very weak• Manifold joint failures


Mechanical Prototype• This module looks very similar to the first

prototype

• It differs in that the fibers are more randomized so that cross connects can strengthen the coupon

• Additional reinforcement at ends was added

• The module was considerably stronger but additional effort is needed

• Coupon still has joint problems


Carbon Carbon Joint Efforts

• Note effects due to 20% shrinkage

• Nanotubes added to increase joint strength

• Still much weaker than conventional epoxy


Ovalized Joined Tubing

Original Design Ovalized Design

Ovalized Glassy Carbon Tube Array


Future Fuzzy Ovalized Carbon Modules

• Ovalized tubing provides thinner cross section

• Fibers connect more directly to the coolant tubes giving much better heat transfer

• Connected carbon tubes are considerably stronger

• The manifold joints clearly need more R&D


“Beryllium” Prototype Modules

Serpentine flow 2mm channel (aluminum)

Parallel flow 2mm channel (aluminum)

Parallel flow 0.5mm channel (stainless steel)


Prototype Flow Test Results

Coupon v3 channel flow position vs. time (0.2 L/min)

0

2

4

6

8

10

12

14

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

time(seconds)

12cm/s

17

1919

17 4.6

Parallel Channel Al Module

Parallel Channel SS Module


Thermal Test Setup• Measure temperatures

using RTD sensors• Heat both surfaces

with brass heat spreaders on silicon wafers.

• Variable flow and heat input

• A vacuum chamber will also be used in future tests


Aluminum Module Heat Tests

• Heating curves at nominal 0.5W/cm2, both sides

• One liter/min flow


Temperature Results

4.5 4.0


Vibration Tests

• Vibrations perpendicular to the surface.

• Vibration vs flow from 0 to 1.5L/min

• Corrected for external vibrations

• All motions are below 1 micron


Pixel Support Module Summary

• We are on track to a workable solution

• We are optimistic that this technology will work.

• This remains our baseline design

• We are moving toward workable solutions

• The Si/Be CTE problem is being studied

• This is a fall-back solution

Fuzzy Fuzzy CarbonCarbon

Beryllium


Materials Testing

• Stress and strain effects

• Vacuum effects

• Neutron activation

• Radiation Damage

What should we be worrying about?


H2O

SourceReceiver Sample

Sound is a pulse with most components in the 1MHz range.

Young’s Modulus Apparatus


Epoxy Study

• Can measure speed of sound to 0.5% from a single measurement.

• From speed of sound, we can know Young’s modulus

• Will measure before/after effects of radiation, stresses, etc.

4 Hour Epoxy

Velocity Studies

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.00 5.00 10.00

Time ( μ )s

Water Signal

10 mm Epoxy

3 mm Epoxy

Initial Pulse

2H O

3mm10mm

T h ic k n e s s ( m m ) 3 . 2 4 5 . 1 7 6 9 . 3 7 3

T r a n s i t T im e ( ? s ) 0 . 8 5 1 . 3 5 2 . 7 2

V e l o c i t y ( m m / ? s ) 2 . 4 6 5 2 . 4 5 6 2 . 4 7 7

A v e r a g e 2 . 4 6 6 + / - 0 . 0 0 8

s t d e v 0 . 4 %

4 H o u r E p o x y


Conclusions

• We have made significant advances in many areas, solving many problems

• Integration issues are now being studied and solutions incorporated into the baseline design

• Many design parameters are much better understood

• There is a lot of remaining work to be done!

Documents

November 16, 2001 C. Newsom BTeV Pixel Modeling, Prototyping and Testing C. Newsom University of Iowa