Post on 31-Dec-2015
description
NuFact 2005
US Solid Target ProgramNeutrino Factory/Neutrino Super Beam
N. Simos, BNL
• H. Kirk, H. Ludewig, PT. Trung (BNL)
• K. McDonald, Princeton U.
• J. Sheppard, SLAC
• K. Yoshimura, KEK
NuFact 2005
What are we after?
• High Intensity/High Power Targets• Low Z or high Z• Alloys, composites, “smart” materials• Stationary solid, granular, rotating• Scrutiny of attractive candidates for irradiation
damage• Driving target scenarios to their limit through
simulations – Use experimental data to back-feed the simulations.
NuFact 2005
Neutrino Super Beam Target Option II: Hollow CC target with He return
CC target
He IN
He OUT
Horn
Insulator
NuFact 2005
SOLID TARGET MATERIAL STUDIES
PHASE I:
Study of Carbon Carbon vs. Graphite under 24 GeV, intense AGS Beam – Shock Response
Irradiation Damage Assessment of Super Invar and Inconel 718
PHASE II:
Irradiation Damage Assessment of a host of attractive candidates.
Re-assessment of Super Invar
Carbon-Carbon Composite in Target Assembly
Nickel-plated aluminum in target assembly (goal is to find out how
irradiation affects bonding)
• Carbon-Carbon Composite (BNL)• Toyota “Gum Metal” (KEK)• Graphite (IG-43) (KEK)• AlBeMet (BNL)• Beryllium (BNL)• Ti Alloy (6Al-4V) (SLAC)• Vascomax (BNL)• Nickel-Plated Alum. (BNL-FNAL-KEK)
Material Matrix of PHASE II Study at BNL
Complex assembly of target materials
BEAM PARAMETERS
200 MeV protons; ~ 70 μA
Spot size FWHM ~ 14 mmBEAM
NuFact 2005
WHY DO WE WANT TO DO THESE TESTS?
IRRADIATION EFFECTS ON GRAPHITEIrradiation has a profound effect on thermal
conductivity/diffusivity.
Is Gum metal the answer to all our issues?How do its superb properties hold up under irradiation?
Does Carbon-Carbon hold its advantage over Graphite other than responding better to shock ?
Non-irradiated HORN material HORN material AFTER irradiation
Is nickel-plating the way to prolong life of HORN?Jury is still out BUT preliminary assessment not favorable
NuFact 2005
What Are We Learning About CC Composite?
Carbon-Carbon Composite Thermal Expansion
-0.03
-0.025
-0.02
-0.015
-0.01
-0.005
0
0.005
0 100 200 300 400 500 600 700
Temp (C)
Th
erm
al S
trai
n (
%)
Unirradiated Carbon-Carbon
Temp. % elongation23 o C 0%200 o C -0.023%400o C -0.028%600o C -0.020%800o C 0%1000o C 0.040%1200o C 0.084%1600o C 0.190%2000o C 0.310%2300o C 0.405%
Experiment
Manufacturer’s DATA
NuFact 2005
GUM Metal
Strengthens but clearly looses “non-linear elasticity”, “super-ductility”Note that irradiation damage of only 0.25 dpa is enough to make the material totally brittle
Irradiation effects on its thermal expansion properties are being assessed
NuFact 2005
Titanium Alloy (Ti-6Al-4v) Stress-Strain Relationship
0
200
400
600
800
1000
1200
0 10 20 30 40
(pseudo) S train (% )
Ti_03_unirrad
Ti-04
Ti-08
Ti-06
Ti-05
Ti-04
NuFact 2005
How reliable are simulations and can we trust them to assess the limits of the target materials ? HADRON CALCULATIONS BENCHMARKING
NuFact 2005
PATH FORWARD
Focus on Carbon Composite
Complete the irradiation damage assessment of a 2-D weave Carbon-Carbon composite (currently under irradiation at BNL). Compare it with the 3-D CC composite.
Continue the simulations performed with the specialized, non-linear code LS-DYNA that allows special modeling of composites such as CC (special license for the benchmarked material has been requested to be integrated with LS-DYNA)
Benchmark the E951 CC target results with the simulation model
Use the simulation model to drive the target to its limit (thus get a feel as to how high in power can we go with CC composites)
Explore the benefits of customization of the fiber arrangement in the composite (presence of weak planes, conductivity enhancement, etc.)
NuFact 2005
Planned Experimental Target Activities
Graphite and Carbon-Carbon to be tested to cycles up to 1100 C in vacuum with forced helium
Thermal diffusivity assessment of irradiated material matrix
Damage assessment due defect generation/growth on the irradiated specimens using ultrasonic techniques (more of an issue in graphite & CC)
Material resilience to shock: Use of a high power, focused laser beam
Expose/irradiate solid targets to much higher energies. P-bar target area at FNAL is being assessed. This will shed light in the possible difference of induced irradiation damage