Monte Carlo Simulation of the Carbon Beam Nozzle for the Biomedical Research Facility in RAON

서지정보

· 발행기관 : 한국의학물리학회
· 수록지 정보 : 의학물리 / 26권 / 1호 / 12 ~ 17페이지
· 저자명 : 배재범, 조병철, 곽정원, 박우윤, 임영경, 정현태

초록

The purpose of the Monte Carlo simulation study was to provide the optimized nozzle design to satisfy the beamconditions for biomedical researches in the Korean heavy-ion accelerator, RAON. The nozzle design was requiredto produce C12 beam satisfying the three conditions; the maximum field size, the dose uniformity and the beamcontamination. We employed the GEANT4 toolkit in Monte Carlo simulation to optimize the nozzle design. Thebeams for biomedical researches were required that the maximum field size should be more than 15×15 cm2,the dose uniformity was to be less than 3% and the level of beam contamination due to the scattered radiationfrom collimation systems was less than 5% of total dose. For the field size, we optimized the tilting angle ofthe circularly rotating beam controlled by a pair of dipole magnets at the most upstream of the user beam lineunit and the thickness of the scatter plate located downstream of the dipole magnets. The values of beamscanning angle and the thickness of the scatter plate could be successfully optimized to be 0.5o and 0.05 cmvia this Monte Carlo simulation analysis. For the dose uniformity and the beam contamination, we introducedthe new beam configuration technique by the combination of scanning and static beams. With the combinationof a central static beam and a circularly rotating beam with the tilting angle of 0.5o to beam axis, the doseuniformity could be established to be 1.1% in 15×15 cm2 sized maximum field. For the beam contamination,it was determined by the ratio of the absorbed doses delivered by C12 ion and other particles. The level of thebeam contamination could be achieved to be less than 2.5% of total dose in the region from 5 cm to 17 cmwater equivalent depth in the combined beam configuration. Based on the results, we could establish theoptimized nozzle design satisfying the beam conditions which were required for biomedical researches.

참고자료

· 없음