N. Simos - LARP (02-03-05)

MATERIAL IRRADIATION STUDIES

FOR HIGH-INTENSITY PROTON BEAM TARGETS AND

COLLIMATORS

BNL AGS/BLIP/Hot Cell FACILITY

Nicholas Simos, BNL

N. Simos - LARP (02-03-05)

SCOPE

ASSESS the effects of proton irradiation on material properties that are key in the design and operation of high power targets and collimators

Experiment is Focused on: Effects of Protons on Graphite

Is proton Irradiation any different than Neutron Irradiation? Are properties of Graphite such as conductivity change as drastically as with neutrons? What are the effects of the surrounding ambient? (air, vacuum, inert gases) Is there an “optimal” operational temperature range?

Is Carbon-Carbon the alternative to Graphite?

How about these new “smart” materials? (Gum metal, AlBemet, etc.)

N. Simos - LARP (02-03-05)

WHY SHOULD WE BE WORRIED?

REACTOR Experience on Graphites and CC composites under neutron irradiation paints a bleak picture:

The key property that we rely on in the collimator (diffusivity and/or conductivity) to transport the beam deposited load can diminish dramatically

Workable scenarios that so far dictate the design already operate close to the limits with unaffected properties

Observe in the following Figures the dramatic effects of irradiation on these materials:

N. Simos - LARP (02-03-05)

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How Do We Make Sure the Collimator Design is based on Best Possible Knowledge of Material Behavior?

Either the design adopts the worst-case-scenario based on existing results from neutron irradiation (i.e. reduce diffusivity by a factor of 8 or 9) in which case it will not make it, or

Experiment with the material under conditions that are close to what the real thing will experience (no arm-waving can work in this case)

ARE WE DOING ANYTHING ABOUT IT?

The answer is YES, but there is need for a “PUSH” to get us to the next level

N. Simos - LARP (02-03-05)

TEST-1: SHOCK Test Using 24 CeV Protons Graphite vs. Carbon-Carbon

N. Simos - LARP (02-03-05)

ATJ Graphite vs. Carbon-Carbon Composite

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

1sr Indicator: CC is the way to goif we care to absorb shock.Do things hold true after irradiation?

N. Simos - LARP (02-03-05)

Previous Studies Focused on Super-Invar

Effect of Heat Treatment in non-Irradiated Invar Samples

0

500

1000

1500

2000

2500

0 0.05 0.1 0.15 0.2 0.25

Extension (mm)

Lo

ad (

N)

non treated Invar

Temp (300 C)

Temp (500 C)

N. Simos - LARP (02-03-05)

Some Alloys Change Drastically and some Don’t

N. Simos - LARP (02-03-05)

Irradiation Studies & POST-Irradiation StudiesCURRENT MATERIAL STUDY MATRIX

• Carbon-Carbon Composite• Toyota “Gum Metal” • Graphite (IG-43) • AlBeMet • Beryllium • Ti Alloy (6Al-4V) • Vascomax • Nickel-Plated Alum.

N. Simos - LARP (02-03-05)

Measuring Irradiation Effects on Material Thermal Expansion, Mechanical properties, thermal conductivity/diffusivity and Thermal Shock

Irradiation Studies & POST-Irradiation Studies

On Going in HOT CELL Facility

N. Simos - LARP (02-03-05)

Irradiation Studies & POST-Irradiation Studies

Material Irradiation – Completed in April 2004

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N. Simos - LARP (02-03-05)

3-D Fine-Weaved Carbon-Carbon Composite Under Study

Temp. % elongation

23 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%

N. Simos - LARP (02-03-05)

Gum Metal (Toyota Ti alloy)

N. Simos - LARP (02-03-05)

N. Simos - LARP (02-03-05)

WHERE ARE WE AND WHAT IS NEEDED TO COMPLETE?

Most Mechanical Testing Completed (currently evaluating the IG-Graphite to be followed by Carbon-Carbon – All other materials done – Data are still in raw form)

During next LARP Video I will have a complete presentation

Graphite and CC composite thermal expansion/swelling are in progress:

Completed evaluation at 300 deg. C and in air Next phase will be at higher temperatures (gradually creeping to 1100 C) and with (a) vacuum and (b) helium)

Preliminary tests of CC up to 600 C indicated that there is either sublimation or oxidation taking place when in air.

Workable scenarios that so far dictate the design already operate close to the limits with unaffected properties

N. Simos - LARP (02-03-05)

WHAT IS NEEDED TO COMPLETE?

Scrutinize Graphite & CC Composite at Higher Temperatures and different environments (biggest problem is the unavailability of funds to use the Hot Cell Facility, it cost me ~ $850/day to operate in one cell)

Following thermal expansion/swelling changes in Graphite & CC perform the most important evaluation:

DIFFUSIVITY/CONDUCTIVITY CHANGES IN THESE MATERIALS

Availability of funds is the sticking problem again

enhance the apparatus to allow for these measurements in the hot cellPay for the extended use of the hot cell facility

OFF-BEAM Shock Resilience of Graphite/CC High Power Laser System ready to go need of funding for a post-doc who is joining me in March