Fig. 1. Diaphragms of different apertures. (a) 16 mm;(b) 12 mm;(c) 8 mm;(d) 5 mm

Fig. 2. Ion beam removal function model of diaphragm in different apertures. (a) 5 mm; (b) 8 mm; (c) 12 mm; (d) 16 mm

Fig. 3. Simulation results of ion beam one-dimensional superposition with 16 mm diaphragm. (a) Superimposed effect; (b) volatility

Fig. 4. Initial profile of fused quartz sample with diameter of 120 mm

Fig. 5. Ion beam simulation of residual variation curves with 16 mm aperture

Fig. 6. Optimal surface shapes of 16 mm aperture with different number of optimizations. (a) Preliminary simulation; (b) 1^st optimization; (c) 2^nd optimization; (d) 3^rd optimization

Fig. 7. Root mean square values of diaphragm at different apertures. (a) 12 mm; (b) 8 mm; (c) 5 mm

Fig. 8. Ion beam simulation surface residual of diaphragm at different apertures. (a) 16 mm; (b) 12 mm; (c) 8 mm; (d) 5 mm

Fig. 9. Residence time distribution

Fig. 10. Surface shape after processing