Fig. 1. The parameter definition in the Doppler broadening spectrum.

Fig. 2. Peak-to-valley ratio of CDB system in the pure iron.

Fig. 3. Calculated localized wave function of a positron trapped in a mono-vacancy bound with one hydrogen atom in tungsten^[26]: (a) Isometric plot; (b) contour plot.

Fig. 4. Calculated positron lifetime in nano-void containing 1 V, 2 V, 6 V, and various H/He atoms^[26].

Fig. 5. Profiles of damage and atom concentration in RAFM steel irradiated with 250 keV He²⁺ and 130 keV H⁺ calculated with SRIM.

Fig. 6. Fitted S parameters versus VEPFIT for irradiated samples.

Fig. 7. Variation of S parameters versus incident positron energy for He⁺ irradiated Fe17Cr14.5Ni alloy during isochronal annealing^[34].

Fig. 8. Evolution of the S parameters in H-ions irradiated FeCu alloys during isochronal annealing^[35].

Fig. 9. S-W plots for the H-ions irradiated samples during isochronal annealing^[35].

Fig. 10. S-parameter and ∆S as a function of positron incident energy (mean implantation depth) in irradiated Fe9Cr alloys and for unirradiated specimen^[36].

Fig. 11. W-parameter as a function of the S-parameter for irradiated Fe9Cr alloys and for unirradiated one^[36].

Fig. 12. Evolution of the S parameters in well-annealed Fe and deformed Fe with He-ions irradiation^[39].

Fig. 13. S-E curves for deformed 304 steel irradiated with He-ions^[40].

Fig. 14. S-parameter (a) and ∆S/S (b) as a function of incident positron energy. ∆S_He + ∆S_H and ∆S_{He + H} parameter were also shown in (c)^[47].

Fig. 15. The S parameter versus depth in the argon-damaged tungsten samples (0/1/6 dpa) with and without deuterium plasma exposure^[48].

Fig. 16. (a) The S parameter versus depth in the tungsten samples, and the (S, W) plots are shown in (b)^[49].

Fig. 17. Evolution of S-E curves in deformed 316 L steel exposed to high flux and low energy helium plasma^[52].

Fig. 18. Evolution of the W parameters in Fe9Cr alloy with He-ions irradiation.

Fig. 19. CDB ratio curves for the Fe9Cr alloy irradiated with a dose of 1 × 10¹⁵ and 1 × 10¹⁶ He⁺/cm^2[63].

Fig. 20. CDB ratio curves for the Ni irradiated with He-ions (a) and for the Cu irradiated with neutron^[66](b).

Fig. 21. CDB ratio curves for the He-ions irradiated 316L samples during isochronal annealing.