Radiation damage study of POCO ZXF-5Q graphite for neutrino production targets using 4.5 MeV helium ions

Journal Article · 04 December 2024 · J.Nucl.Mater.

DOI: https://doi.org/10.1016/j.jnucmat.2024.155545 · OSTI ID:2530130

Burleigh, Abraham  ^[1]; Ammigan, Kavin  ^[2]; Bidhar, Sujit  ^[2]; Pellemoine, Frederique  ^[2]; Toader, Ovidiu ^[3]; Kubley, Thomas ^[3]; Sun, Kai ^[3]; Terry, Jeff ^[1]

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1. IIT, Chicago
2. Fermilab
3. Michigan U.

To address the challenges of increased beam power and target survivability associated with next-generation particle production beam lines, high dose, high-energy proton beam conditions are simulated using irradiation from low-energy ion beams. A low-energy ion irradiation study of POCO ZXF-5Q graphite under conditions similar to those of the NuMI NT-02 neutrino production target at the Fermi National Accelerator Laboratory is reported. Helium ion irradiation was performed at ${100}^{\circ }\text{ C}$ to a maximum damage level of 0.9 displacements per atom (DPA). Irradiation induced hardening, swelling of the irradiated region, inter-plane lattice expansion, and intraplane lattice contraction with increasing ion fluence was observed using micromechanical (nanoindentation, atomic force microscopy) and electron microscopy (high-resolution imaging, selected area diffraction) characterization. Similar changes were also observed in post irradiation examination of the NT-02 target indicating that ion irradiation can be a valuable tool for estimating radiation damage in proton beam targets. Caution must be exercised though, because the hardening, lattice alteration, and swelling occur to different magnitudes for a given damage level. The observed hardening and embrittlement were greater for ion irradiated graphite. For He ion irradiated samples the lattice spacing changes were smaller at low damage levels (78% less expansion and 71% less contraction at 0.1 DPA) and larger at high damage levels (38% more expansion and 5% more contraction at 0.9 DPA) relative to that observed in the NT-02 target. The magnitude of swelling was 8.5× greater under ion irradiation which is influenced by the differing damage gradients and inclusion of implanted He ions in the region of interest.

• Research Organization: Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); IIT, Chicago; Michigan U.
• Sponsoring Organization: US Department of Energy
• Grant/Contract Number: 89243024CSC000002; AC02-07CH11359
• OSTI ID: 2530130
• Report Number(s): FERMILAB-PUB-24-0006-AD; oai:inspirehep.net:2859667
• Journal Information: J.Nucl.Mater., Journal Name: J.Nucl.Mater. Vol. 605
• Country of Publication: United States
• Language: English