1

Energy Science Laboratories, Inc.Materials & Processing ESLI

Cooled Carbon Support Cooled Carbon Support BTeV Pixel DetectorsBTeV Pixel Detectors

Development Recommendations for 2001

T R Knowles3/7/01

2

Energy Science Laboratories, Inc.Materials & Processing ESLI

FY00 Progress• Cooled carbon structure demo articles (full-scale)

– Lightweight – Rigid– Shingled surface– Porous chip mount – Al manifolds

• Issues– Resistance at tube wall is high

• Need to increase thermal conductance – Tubing cracked, leaked

• Need to increase toughness and assure leak-tightness

Fibrous surface for shingling with high contact conductance

Vertical high-k fibers with in-plane discrete fiber reinforcements

Tubes cemented in grooves

3

Energy Science Laboratories, Inc.Materials & Processing ESLI

Increase Thermal Conductance• “Fintubing” Concept

– Improved fiber orientation – Issues: Precision? Manifolds?

• “Tubewall” Concept– Complete layer of tubing

• Tubing height < 1 mm – Issues: Precision, Rigidity?

Manifolds

4

Energy Science Laboratories, Inc.Materials & Processing ESLI

Graphite Header Tubing• Sealed POCO graphite tube

– Tube machined from POCO – Pyrocarbon CVD seal coat

• Helium leak test – Light CVD seal reduced He

permeation to <5e-9 mL/s (most sensitive scale on leak detector)

– Expect heavier coat to seal even better (no helium leak signal)

• Good candidate for headers– May reinforce with carbon braid

to improve strength and toughness

POCO graphite rod

CVD POCO tube, (unreinforced – 8 ksi)

5

Energy Science Laboratories, Inc.Materials & Processing ESLI

Tube Manifolding

• Carbon carbon construction– Tubular elements

• Large-gauge headers• Small-gauge lines

– Carbon joining• Carbonize bonding resin• Seal by pyrocarbon CVD

• Reinforcement options– Integral boss on graphite

header for larger tube/header interface

– Fabric reinforcements

6

Energy Science Laboratories, Inc.Materials & Processing ESLI

FY01 Task 1Review Issues and Options

• THERMAL “fintube” and “tubewall” options– Fabricate small comparison articles

• STRUCTURAL fibercore; carbon fiber frame – Fabricate small comparison articles

• MANIFOLDING aluminum vs carbon – Fabricate carbon-carbon T-joint to test hermiticity

• TOUGHNESSreliable tube/manifold connection– Fabricate stress-relieved joints with velvet or fabric

7

Energy Science Laboratories, Inc.Materials & Processing ESLI

FY01 Task 2Fabricate Prototypes

• Fabricate two (2) Cooled-Carbon Supports – Incorporate design features selected from Task 1

• Assure leak-tightness by monitoring throughout fabrication• Mount on aluminum frames; attach inlet and outlet lines

• Preliminary heat exchanger performance test at ESLI– Measure flow impedance– Measure heat exchanger performance

• Theater - Tcoolant when symmetrically heated @ 1 W/cm2

8

Energy Science Laboratories, Inc.Materials & Processing ESLI

FY01 Task 3Superstructure Options

• Work together with FNAL engineering to draft design of support superstructure based on – Lightweight sandwich structures– Carbon tubing – Carbon truss superstructures

carbon rod space framebulkheads

9

Energy Science Laboratories, Inc.Materials & Processing ESLI

Carbon Truss Structure Concept• Carbon sheet (100 µm) bulkheads• Carbon-fiber rods in tension• Carbon tubing & manifolds• Carbon fibercore thermal area

10

Energy Science Laboratories, Inc.Materials & Processing ESLI

Cost/Schedule

Task Time (months) Cost ($k)

1. Design Selection 2 25

2. Prototype Fabrication 4 75

3. Superstructure 1 15