Fig. 1. Diagram of experimental principle

Fig. 2. Labeling method of the sample grid cell

Fig. 3. Geometric settings of each area in the sample

Fig. 4. Prompt gamma ray counting distribution of Fe in different positions of the sample

Fig. 5. Prompt gamma ray counting distribution of H in different positions of the sample

Fig. 6. PGAI reconstruction result for Fe

Fig. 7. PGAI reconstruction result for H