Fig. 1. (a) Schematic of the experimental setup for nuclear isomer ^152mEu production at the XingGuangIII laser facility, (b) Schematic of the ^152mEu production of photo-nuclear reaction, (c) Partial energy level transition scheme for the ^152mEu nucleus (right side of the panel shows the level energies, and the left side shows the half-lives and valence state)

Fig. 2. (a) Electron energy distribution map recorded by the IP plate, (b) Electron energy spectrum detected by the electron spectrometer

Fig. 3. (a) Cross section of ¹⁵³Eu(γ, n)^152m1,m2Eu photo-nuclear reaction, (b) Simulated bremsstrahlung spectra of the anterior surface of the Eu₂O₃ target, among them, ¹⁵³Eu(γ, n)^152m1,m2Eu nuclear reaction mainly occurs in the pink region (color online)

Fig. 4. (a) Total gamma spectrum of the Eu₂O₃ target with a detection time of 40 h, (b) Peak counts accumulated for three characteristic γ-ray lines at energies of 841.6 keV and 963.4 keV

Fig. 5. Distribution of ^152m1Eu (a) and ^152m2Eu (b) in the X-Z plane within the target zone, and that of ^152m1Eu (c) and ^152m2Eu (d) in the X-Y plane within the target zone

Fig. 6. Yield of ^152m1Eu varies with the thickness of the target (Eu₂O₃) at the fixed Ta target thickness of 2 mm

Fig. 7. Variations of the yield (a), production time (b), and peak excitation efficiency (c) of ^152m1,m2Eu with electron temperature

Table 1. Production yields of ^152m1Eu and the key parameters used for yield calculation