Harold G. KirkBrookhaven National Laboratory

Post-Irradiation Properties of Candidate Materials for High-Power Targets

PAC05

Knoxville, TN May 16-20, 2005

Harold G. Kirk

Pressure Wave Amplitude

Stress = Y αT U / CV

Where Y = Material modulus

αT = Coefficient of Thermal Expansion

U = Energy deposition

CV = Material heat capacity

When the pressure wave amplitude exceeds material tensile strength then target rupture can occur. This limit is material

dependant.

Harold G. Kirk

E951: Graphite & Carbon-Carbon Targets

ATJ CC

X/U

Y, GPa 10 54/5.3

αT ,

10-6/0K

2.5 ~0

Tensile

Strength, MPa

15 182/44

Key Material Properties

Harold G. Kirk

24 GeV, 3 x 1012 protons/pulse

BNL E951 Target Experiment 24 GeV 3.0 e12 proton pulse on Carbon-Carbon and ATJ graphite targets

Recorded strain induced by proton pulse

-8

-6

-4

-2

0

2

4

6

8

10

0 0.0002 0.0004 0.0006 0.0008 0.001

Time (sec)

Mic

ros

tra

in

C-C composite

ATJ Graphite

E951: Strain Gauge Measurements

Harold G. Kirk

Target Material Examples

Peter Thieberger, BNLConsider the case of a 16 x 1012 , 3ns , 24 GeV proton pulses

Maximum initial stress as % of yield stress for the 1 MW option.

1

10

100

1000

10000

1 2 3 4 5 6 7 8 9

Target Radius (mm)

% o

f Y

ield

Str

ess

Iron

Inconel 718

Vascomax 350

Super Invar

Beam Induced StressMaterial Yield Strength

Harold G. Kirk

Super-Invar Irradiation at BNL (2002)

The targetbasket afterirradiation

The cylindricalsamples of super-invar.

Dilatometer inHot Cell

Tensile Testerin Hot Cell

Harold G. Kirk

Super-Invar CTE measurements

Peak Proton fluence1.3 x 1020 protons/cm2

Harold G. Kirk

Super-Invar Tensile Testing

Tensile testing shows that Super-Invar strengthens while remaining ductile (at the 0.25 dpa level)

Harold G. Kirk

Irradiation at BNL (2004)

Harold G. Kirk

Material Test Matrix

Carbon-Carbon composite: Low-Z, low CTE composite that may potentially minimize thermal shock and survive high intensity pulses.Graphite (IG43) : Different graphite grades respond differently to irradiationTitanium Ti-6Al-4V alloy: Irradiation effects on fracture toughness of alloy that combines good tensile strength and relatively low CTE are soughtToyota’s “Gum” Metal : “Super” alloy exhibiting ultra-low elastic modulus, high strength , super-elastic like nature and near-zero linear expansion coefficient for the temperature range -200 C to +250 C Vascomax: High-strength, high-Z alloy. Irradiation effects on CTE, fracture toughness and ductility loss are sought.Beryllium: Known material examined closer for irradiation damageAlBeMet: Low-Z composite combining good properties of Be and Aluminum.Nickel-plated Aluminum (NUMI horn) : Assess how bonding between the layer and the substrate survive irradiation in the presence of waterSuper-Invar: Re-examination of previously tested material for effects of temperature induced annealing

Harold G. Kirk

Carbon-Carbon Composite

Average Proton Fluence

( 1020 protons/cm2)

0.76

{ 0.52 and 0.36

0.13

none

Harold G. Kirk

C-C Composite Thermal Cycles

XYZ Orientation UV Orientation

Harold G. Kirk

CTE resetting of Super-Invar

Invar resets its CTE after a 6000C thermal cycle

Harold G. Kirk

Super-Invar thermal cylcles

Harold G. Kirk

Additional CTE Results

Harold G. Kirk

Initial Tensile Results

Vascomax Stress-Strain

0

200

400

600

800

1000

1200

1400

0 10 20 30 40

strain (% )

Unirradiated

Vasco-22

Vasco-23

Vasco-24

Gum Metal strengthens but turns brittle Vascomax strengthens without turning brittle.

Harold G. Kirk

The Collaborators

H. Kirk, H. Ludewig, L. Mausner, N. Simos, P. Thieberger

Brookhaven National Laboratory

K. McDonald

Princeton University

J. Sheppard

Stanford Linear Accelerator Center

L. P. Trung

Stony Brook University

Y. Hayato, K. Yoshimura

KEK