Study On Calibration Of Proton Absorbed Dose Of Alanine With Faraday Cup

This paper introduced a method of calibration absorbed dose of alanine with faraday cup at proton beam and designed a new kind of faraday cup named limited opening faraday cup(LOFC).The performance of LOFC is superior to traditional faraday cup,which has been proved by measuring with accelerators and simulating with Ansoft.Through the several approaches such as beam scattering system design, beam monitoring system design,and data acquisition system study,this paper established a set of film dosimeter calibration system with faraday cup.Through analyzing beam scattering system,this paper presented the multi-scattering films theory,which is scattering angle of multi-films is larger than single-film when the proton energy loss is the same.We obtained alanine response curve of 2kGy～30kGy rang,and measured alanine Bragg peak absorbed dose at 10MeV proton beam.At last, we evaluated the uncertainty of calibrating proton absorbed dose of alanine with faraday cup,obtained the proton level ground absorbed dose of alanine uncertainty is 3.55%,and proton Bragg peak absorbed dose of alanine uncertainty is 3.73%.