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This is very important as it allows confident identification of defects that are caused by helium exposure. Remarkably, the strain distribution revealed that helium-induced defects have random orientation, and that fewer defects exist near grain boundaries, suggesting that perhaps nanostructured materials may offer better radiation resistance. These new insights are key to developing new strategies for

designing the next generation of radiation damage- resistant materials.

The data for this study was collected before the ESRF- EBS upgrade, after which the ID01 beamline delivers over 20 times more coherent flux to the sample position. Therefore, the future is bright when it comes to Bragg

Fig. 71: a) Tungsten is used as an armour material to protect the reactor vessel from the fusion plasma. In service, armour components will be exposed to intense ion and neutron bombardments (image adapted from EUROfusion; CC BY 4.0 licence.). b) Crystalline strain distribution produced by helium ion bombardment into tungsten shown on cut planes through the measured sample. These make it possible to visualise the helium-implanted layer, which shows increased strain due to the presence of atomic-scale point defects and (c) lattice tilts. d) Dislocations propagating through the crystal could be imaged and compared to physical models.