1. Overview of radiation damage studies and the RaDIATE Collaboration
M. Calviani (CERN)
P. Hurh (FNAL, RaDIATE program coordinator)
R. Ferriere, M. Timmins, E. Fornasiere, A. Perillo-Marcone, D. Horvath, C. Torregrosa (CERN) + Makimura (J-PARC)

2. M. Calviani - RaDIATE & CERN application
Introduction
A new collaboration was started few years ago to cope with the lack of data concerning radiation damage in accelerator target environments
Triggered by FNAL within the scope of the LBNF project and NuMI, i.e. for neutrino targets…
… It took a more global scope when labs with different “requirements” joined the team (spallation, p-bar, beam windows, etc.)
1 February 2017
M. Calviani - RaDIATE & CERN application

3. Radiation Damage In Accelerator Target Environments
RaDIATE
Collaboration
Radiation Damage In Accelerator Target Environments
Broad aims are threefold:
to generate new and useful materials data for application within the accelerator and fission/fusion communities
to recruit and develop new scientific and engineering experts who can cross the boundaries between these communities
to initiate and coordinate a continuing synergy between research in these communities, benefitting both proton accelerator applications in science and industry and carbon-free energy technologies
radiate.fnal.gov
Currently adding CERN and J-PARC to the MOU
P. Hurh, FNAL

4. n p Radiation Damage Irradiation Source DPA rate (DPA/s)
1-14 MeV p
100+ MeV
Irradiation Source
DPA rate (DPA/s)
He gas production (appm/DPA)
Irradiation Temp (˚C)
Mixed spectrum fission reactor
3 x 10-7
1 x 10-1
Fusion reactor
1 x 10-6
1 x 101
High energy proton beam
6 x 10-3
1 x 103
14.9 DPA
23.3 DPA
Add note that use of data from nuclear materials research is limited and should not be depended upon.
Effects from low energy neutron irradiations do not equal effects from high energy proton irradiations. Table compares typical irradiation parameters.
Cannot directly utilize data from nuclear materials studies!
P. Hurh, FNAL
1 February 2017

5. High Energy Physics HPT Future Needs
Exp/Facility
Laboratory
Time frame (yrs)
“On the books”?
Beam Power (kW)
Comments
ANU/NOvA
FNAL
0.1 Y
700
Full power soon
T2K
J-PARC 2
750
Ramping Up!
LBNF-1.2 MW 10
1,200
PIP-II enabled
T2K Upgrade
10? ?
1,300
~4 MW long-term?
Next-Gen Nu Facility –2.5 MW
20? N
2,500?
Mid-Term
Next-Gen Nu Facility - 5 MW
30?
5,000?
Longer-term
BDF
CERN
10 ?
Y/N
500
High-Z target
Future beam power and intensities present major challenges to reliable and efficient high power target facilities
Other low power (but high intensity) target facilities will also be needed. Notably follow-on experiments to Mu2e/COMET, CERN AD-T, CERN n_TOF, TIDVG absorber etc… These are still challenging targets due to high-Z targets and small beam spots, but are not listed here.
P. Hurh, FNAL + Marco

6. Targetry (and beam absorbers) scope
Solid, liquid, rotating, rastered
Other production devices:
Collection optics (horns, solenoids)
Monitors & instrumentation
Beam windows
Facility requirements:
Remote handling
Shielding and radiation transport
Air handling
Cooling systems
Important applicability to CERN BIDs, such as production target (AD, n_TOF, BDF) and beam absorbers (TIDVGs, LHCTDE, FCCTDE etc.) which – already now – receives significant amount of beam
1 February 2017
M. Calviani - RaDIATE & CERN application 6

7. High power/intensity targetry challenges
Material behavior
Thermal “shock” response
Radiation damage
Highly non-linear thermo-mechanical simulation
Targetry technologies
Target system simulations (physics & reliability)
Rapid heat removal
Radiation protection
Remote handling
Radiation accelerated corrosion
Manufacturing technologies
Main focus within RaDIATE
1 February 2017
M. Calviani - RaDIATE & CERN application

8. Radiation Damage 0 DPA 3.2 DPA 14.9 DPA 23.3 DPA
Displacements in crystal lattice (expressed as Displacements Per Atom, DPA)
Embrittlement
Creep
Swelling
Transmutation products
H, He gas production can cause void formation and embrittlement (expressed as atomic parts per million per DPA, appm/DPA)
Fracture toughness reduction
Thermal/electrical conductivity reduction
Coefficient of thermal expansion
Modulus of Elasticity
Fatigue response
Dependent upon material condition and irradiation conditions (e.g. temp, dose rate)
0 DPA
3.2 DPA
One notes that all the properties that are important for thermo-mechanical health of the target are affected by radiation damage. The dependence on irradiation temperature is due to annealing (or healing) the crystal structure is faster at higher temperatures.
14.9 DPA
23.3 DPA
S. A. Malloy, et al., Journal of Nuclear Material, (LANSCE irradiations)
P. Hurh, FNAL
1 February 2017

9. Examples of radiation damage
D.L. Porter and F. A. Garner, J. Nuclear Materials, 159, p. 114 (1988)
Factor of 10 reduction in conductivity at 0.02 DPA
Void swelling in 316 Stainless steel tube (on right) exposed to reactor dose of 1.5E23 n/cm2
N. Maruyama and M. Harayama, “Neutron irradiation effect on … graphite materials,” Journal of Nuclear Materials, 195, (1992)
P. Hurh, FNAL
1 February 2017

10. The High Costs of High-Energy Radiation Damage Studies
High energy, high fluence, large volume proton irradiations are needed to entirely replicate the HEP target environment and provide “bulk” samples for analysis
High cost of irradiation “station” (4+ M$)
Beam line and building not included in cost estimate
High cost of irradiation beam time (0.5 M$ per 12 weeks)
High cost of Post-Irradiation Examination (PIE) of activated samples (20+ k$ per sample) $$ $$
High-Energy irradiations including PIE are expensive and can take a very long time
P. Hurh, FNAL
1 February 2017

11. Low Energy Ion Irradiations Instead?
Fission and Fusion materials R&D community (e.g. University of Michigan Ion Beam Laboratory, MIBL ++ Europe as well)
Positives:
Low to zero activation (PIE in “normal” lab areas)
Greatly accelerated damage rates (several DPA in a day)
Significantly lower cost irradiations
Negatives:
Very shallow penetration (0-10 microns)
Little gas production in samples
Promising Solutions:
Micro-mechanics may enable evaluation of critical properties
Simultaneous implantation of He and H ions (triple-beam irradiation)
But still need HE proton irradiations to correlate and validate techniques ¢¢ ¢¢
P. Hurh, FNAL
1 February 2017

12. Brief outlook on RaDIATE R&D
181 MeV p BNL’s BLIP facility
2017 BLIP Irradiation (see later)
NuMI Be window PIE & future work (FNAL, Oxford)
Helium implantation study at Surrey/Oxford
In-beam thermal shock test of Be at CERN’s HiRadMat
2018 HRMT tests with BLIP irradiated materials
NuMI target (NT-02) autopsy and graphite PIE ++ potential CNGS?
Meso-scale fatigue testing (Oxford)
Other complementary studies on C, graphite and Ti64
1 February 2017
M. Calviani - RaDIATE & CERN application

13. M. Calviani - RaDIATE & CERN application
2017 BLIP run
Organized by the RaDIATE Collaboration
Includes graphite at various temperature (up to 1000 C)
Also Be, Ti alloys, Si, TZM, Al, CuCrZr, Ir, SiC-coated C
Post-irradiation examination (2018) includes mechanical, thermal, microstructural and fatigue evaluation
Participants: BNL, PNNL, FRIB, ESS, CERN, JPARC, STFC, Oxford, LANL
1 February 2017
M. Calviani - RaDIATE & CERN application

14. CERN application in the BLIP run
Complement long-term radiation damage effects on materials used for targets (AD-target) and dump application
Study of evolution of plastic deformation and fracture for irradiated materials at different temperatures for future targets and dump application
Mean: Assess bulk mechanical properties of irradiated materials
Materials: Iridium (AD-T), TZM (BDF + AD-T + ??), CuCrZr (TIDVG), Silicon (absorbers)
Foreseen mechanical tests  4 point-bending tests
Iridium, TZM, CuCrZr: 40 samples each (20x2x0.5 mm)
Silicon: 40 samples (40x2x1 mm)
1 February 2017
M. Calviani - RaDIATE & CERN application

15. CERN application in the BLIP run
Irradiation: proton beam between 120 MeV and 130 MeV and 150 mA for 2 weeks at BLIP facility at Brookhaven National Laboratory (BNL)
Expected DPA over the two weeks run
0.32 in iridium
0.14 in TZM
0.18 in CuCrZr
Reached irradiation temperature of ~900 °C
1 February 2017
M. Calviani - RaDIATE & CERN application

16. M. Calviani - RaDIATE & CERN application
Objectives of the run
Re-design of new irradiation capsule in order to accommodate samples, optimize e-beam welding and vacuum inside the capsule
Irradiation foreseen 27th February
Samples will be ready for analysis from mid after cool-down period
Parallel tests at CERN for non-irradiated ones
PIE: 4 point-bending mechanical tests at several temperatures (up to 1200°C)
Tests to be realized at Pacific Northwest National Laboratory (PNNL)
1 February 2017
M. Calviani - RaDIATE & CERN application

17. Proposed configuration
1st Layer
2nd Layer
3rd Layer
4th Layer
Total thick.
Energy budget (MeV)
Sample
Sample + SS windows
High-Z Capsule Ir
0.5 mm
TZM
CuCrZr
Flexible graphite
0.1 mm
1.6 mm
7.19
9.23
Si Capsule
SiC-Coated Graphite
1 mm
Poly-Si
2 mm
5 mm
3.95
5.74
1 February 2017
M. Calviani - RaDIATE & CERN application 17

18. M. Calviani - RaDIATE & CERN application
Sample geometry
Same sample geometry for all four materials (Ir, TZM, CuCrZr, Si)
Samples placed in a 40mm x 40mm square in the center of the capsule
Only 4-point bending tests foreseen RT
500oC (TBC)
800oC (TBC)
40 samples of dimensions
20 x 2 x 0.5 mm for Ir, TZM, CuCrZr
40 x 2 x 1 mm for Si
All samples are engraved
Could this geometry be used for measurement of thermal properties?
1 February 2017
M. Calviani - RaDIATE & CERN application 18

19. M. Calviani - RaDIATE & CERN application
High-Z Capsule
Capsule
Flexible graphite
Graphite filler
CuCrZr
samples
TZM samples
Cover
Ir samples
0.3mm SS
0.3mm SS
Cut view of High-Z capsule
1 February 2017
M. Calviani - RaDIATE & CERN application 19

20. Si Capsule Cut view of Si capsule Capsule Graphite filler
SiC-coated graphite samples
Si samples
Si filler
Si samples
Flexible graphite
Cover
0.3mm SS
0.3mm SS
Cut view of Si capsule
1 February 2017
M. Calviani - RaDIATE & CERN application 20

21. SiC-coated Graphite Samples
SiC coated graphite for application to muon targets
Toyo Tanso Samples
0.76 mm graphite, density; 1.85 g/cc
0.12 mm SiC coating on both sides, density; 3.2 g/cc
3 samples (1 center + 2 periphery), effective density; 2.17 g/cc.
Ibiden Samples
0.82 mm graphite, density; 1.75 g/cc
0.09 mm SiC coating on both sides, density; 3.2 g/cc
2 samples, effective density; 2.01 g/cc
Filler: IG-430U (Toyo Tanso). density; 1.82g/cc
1 February 2017
M. Calviani - RaDIATE & CERN application 21
by S. Makimura

22. Thermal Analysis – Low Density Capsule
Temperatures
Thermal Expansions:
Initial lateral gaps Samples-Fillers = 0.1 mm
Initial lateral gap Fillers-SS capsule = 0.2 mm
Max T Si samples:
216 ºC
Max T Graph/SiC:
Max T Sigraflex:
193 ºC
Max T SS window:
71 ºC
Remaining gap Graph/SiC –Filler: 94 um
Remaining gap Si samples – Si Filler: 80 um
Remaining Fillers– SS Capsule: 200 um
(remains the same)
Max HF SS window-Water:
28 W/cm2
T profile at the center of the capsule
Graph/SiC samples
Si samples
Flexible (Sigraflex) graphite SS SS
*Assumed TCC in Back-up slides
1 February 2017
M. Calviani - RaDIATE & CERN application 22

23. Thermal Analysis – Heavy Capsule
Temperatures
Thermal Expansions:
Initial lateral gaps Samples-Fillers = 0.1 mm
Initial lateral gap Fillers-SS capsule = 0.2 mm
Max TZM samples:
610 ºC
Max T Ir:
300 ºC
Max T Flex Graph:
210 ºC
Max T SS window:
116 ºC
Remaining gap Heavy samples–Filler: 0
(contact, but displacement is absorbed by filler-SS gap)
Remaining gap Filler–SS : Increases 20 um
Max HF SS window-Water:
50 W/cm2
T profile at the center of the capsule
Flex Graph Layer
TZM samples
Ir samples SS SS
*Assumed TCC in Back-up slides
1 February 2017
M. Calviani - RaDIATE & CERN application 23

24. PIE @ PNNL – Mechanical properties I
With the courtesy of D. Senor (PNNL) – ATS
1 February 2017
M. Calviani - RaDIATE & CERN application

25. PIE @ PNNL – Mechanical properties II
With the courtesy of D. Senor (PNNL) – ATS
1 February 2017
M. Calviani - RaDIATE & CERN application

26. M. Calviani - RaDIATE & CERN application
Conclusions
The RaDIATE Collaboration has been active for the past ~3 years and is starting to produce results benefitting primarily HEP targetry global community (KEK, FNAL, CERN)
Current and planned activities will also now directly benefit the Nuclear Physics and Spallation source communities (FRIB, ESS, CERN)
Radiation damage and thermal shock are highest priority
Fundamental limits of solid materials
Mechanisms and conditions unique to accelerator target facilities
Sustained efforts with multiple approaches
Provides an important framework for information exchange and optimization of irradiation run as well as design
1 February 2017
M. Calviani - RaDIATE & CERN application