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