CIAE, Beijing, People’s Republic of China
Fixed Field Alternating Gradient Accelerators have been developed for decades. A continuous wave (CW) 2 GeV FFA which aims at high-power proton beam applications is under developing in China Institute of Atomic Energy (CIAE). To avoid dangerous resonance lines and manipulate the tune diagram flexibly, 3rd order magnetic field is applied along the radius and 10-fold symmetrical F-D-F scheme has been proved to be feasible. In this paper, Integral Equation Method (IEM) is introduced and shown more efficient than adjusting the variable gap manually, saving time for magnet design. First of all, the radial mean field is set as a main design goal and the Δ H at different radii is solved by linear equations based on IEM. The isochronism is done when the mean field is well matched with the design value, whereas some precise corrections are needed for the oscillating frequency Vr and Vz, such as fringe field effects and multipole components near the end of pole face. The tune shift caused by fringe field is also included in this paper. Fringe field is more crucial for HTS magnets especially, since the leaked field of superconducting coil is ~1 kGs. Considering that, we apply an angular matching method to compensate the tune shift by fringe field.
HUST, Wuhan, People’s Republic of China
Due to the PB algorithm’s limited accuracy, a higher accuracy dose verification tool is a legal requirement for proton therapy. Therefore, we developed an automated treatment plan dose verification framework based on the Monte-Carlo (MC) algorithm .The MC beam model was derived from commissioning data and fed into our automated software. CT and treatment plan from TPS were input for the automated software. The developed tool was validated and compared with the PB algorithm of Pinnacle3 TPS for 85 prostate patients. The difference between the PB dose and the MC dose of our automated tool was evaluated using gamma analysis (3 mm/3%, and 2mm/2% criteria) and mean absolute errors. Although the result shows good agreement and the passing rate was about 95%, the difference of all the indices was found to increase as the degree of tissue heterogeneity increased. The MC dose has a higher MAE in CTV, and femoral head compared to the PB dose. The automated software can facilitate patient plan verification in institutions and be useful for other clinical applications.