N. Simos - LARP ( ) MATERIAL IRRADIATION STUDIES FOR HIGH-INTENSITY PROTON BEAM TARGETS AND COLLIMATORS BNL AGS/BLIP/Hot Cell FACILITY Nicholas Simos, BNL

N. Simos - LARP ( ) 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 ( ) 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 ( )

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

N. Simos - LARP ( ) ATJ Graphite vs. Carbon-Carbon Composite 1sr Indicator: CC is the way to go if we care to absorb shock. Do things hold true after irradiation?

N. Simos - LARP ( ) Previous Studies Focused on Super-Invar

N. Simos - LARP ( ) Some Alloys Change Drastically and some Don’t

N. Simos - LARP ( ) Irradiation Studies & POST-Irradiation Studies CURRENT 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 ( ) 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 ( ) Irradiation Studies & POST-Irradiation Studies Material Irradiation – Completed in April 2004

N. Simos - LARP ( )

3-D Fine-Weaved Carbon-Carbon Composite Under Study Temp.% elongation 23 o C0% 200 o C-0.023% 400 o C-0.028% 600 o C-0.020% 800 o C0% 1000 o C0.040% 1200 o C0.084% 1600 o C0.190% 2000 o C0.310% 2300 o C0.405%

N. Simos - LARP ( ) Gum Metal (Toyota Ti alloy)

N. Simos - LARP ( )

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 ( ) 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 cell  Pay 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