The Study Of Detector Systems For The Projectile Breakup And Beam Monitor On Carbon Ion Therapy

The depth-dose profile-Bragg curve, high relative biological effectiveness, andsmall lateral scattering makes carbon ion beams become the best choice for radiationtherapy.When the clinical treatment by using high-energy carbon ions, the probability ofnuclear reaction is much smaller, but the charged fragmentations and neutrons whichare produced in the nuclear reaction will lead to significant effects at large penetrationdepths or at large spread, and the healthy tissues out the target area can be hurt. Forestimating the hurt to normal tissue caused by that particles and optimizing thetreatment plan with the consideration of the nuclear reactions in clinical treatment, thecross section of the light fragmentations and neutrons should be obtained. For thatreason, a special detector system had been developed. The system is comprised ofwater target, start detectors, charged particle detectors, and neutron detectors. Usingthis detector system, charged particles and neutrons were measured in a round ofexperiments. The experiments show that, charged particles with1≤Z≤6can bedifferentiated properly by E-E telescope method and E-TOF method; neutrons canbe discriminate from gamma-rays and charged fragments very well by TOF andanti-coincidence methods. The differential cross-section of the elements with Z=1and2, and the differential flux section of the neutrons were got form the experiments. Theexperiments results achieved the anticipation. The high-quality carbon ion beams arethe prerequisite for delivery of the dose with millimeter precision. Meanwhile,beam’s position and distribution monitor system in a no invasion way with rapidfeedback function is essential in the clinical treatment. In this paper, an online beam’s position and distribution monitor system had been developed using new technology.The detector’s total material thickness is not beyond12μm, position resolution isbetter than1mm. The front end electronics, with high integration and small size, havewide dynamic range to satisfy the requirement of changes in the beam intensity. Alsoa new technology, which converts a parallel input into a serial output, was adopted toreduce the number of channels need by data acquisition system. Using the detectorsystem can ensure the accuracy of beam delivery. Besides, in this paper, a beamdiagnosis detector system had been developed for high energy beam line, which canget the beam’s profile, position and full width at half maximum quickly.