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

Insulator

He IN

Solid CC target

NuFact 2005

Neutrino Super Beam Target Option II: Hollow CC target with He return

CC target

He IN

He OUT

Horn

Insulator

NuFact 2005

Rotating Band (Muon Collider)

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

Irradiation Set-up

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

How much irradiation damage do we induce ?

NuFact 2005

Super Invar re-assessment

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

Beam Window Experiment (E951) Experimental Strain Data vs. Simulation

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