Fig. 1. Layout of superconducting cyclotron CYCIAE-230 and beam line layout (cyclotron to gantry entrance)

Fig. 2. Structure diagram of degraderand collimator

Fig. 3. Energy distribution at the exit of the collimator COL2 (a) 230 MeV (bin: 0.05 MeV), (b) 70 MeV (bin: 0.25 MeV)

Fig. 4. Distribution map of horizontal beam in phase space in the exit plane of the degrader (a) and the exit plane of the collimator COL2 (c) at the 230 MeV energy setting; Distribution map of horizontal beam in phase space in the exit plane of the degrader (b) and the exit plane of the collimator COL2 (d) at the 70 MeV energy setting

Fig. 5. Distribution map of horizontal beam in phase space with phase ellipse for 70 MeV energy settings

Fig. 6. 2σ values of transverse divergence (a) and emittance (b) of the protons in the beam core at the exit of the degrader and the collimator COL2

Fig. 7. Comparison of simulated beam transport results at different initial envelope radius and divergence (2σ)

Fig. 8. Transverse half-envelope sizes for beam transport to different slit positions with different initial envelope radius and divergence (2σ) (a) SL1X, (b) SL1Y, (c) SL2X

Fig. 9. Overall beam transport results (2σ) for five energy settings with energies at 70 MeV, 110 MeV, 150 MeV, 190 MeV and 230 MeV

Fig. 10. 2σ values of transverse divergence (a) and emittance (b) at the COL2 exit before and after the beam is limited

Fig. 11. Beam transmission efficiency for five energy settings at 70 MeV, 110 MeV, 150 MeV, 190 MeV and 230 MeV