STUDY OF THE APF TYPE COMPACT CANTHER THERAPY SYSTEM

为加速用于紧凑型肿瘤治疗系统注入器的高能重离子束，研制了一台采用直接等离子体注入方案(DPIS)的RFQ直线加速器。DPIS-RFQ聚束器直线加速器是为了确认碳离子加速特性而设计的。其工作频率为100 MHz。由美国国家放射科学研究院(NIRS)研制的DPIS-RFQ直线加速器和CO2激光离子源组成的束流试验台。我们利用该系统成功地加速了50 mA的碳离子束，并于2004年7月创造了国际纪录。在德国举行的国际直线加速器会议(Linac2004)和日本粒子加速器学会会议上报告了研究结果。为了实现紧凑型重离子癌症治疗系统，全条纹碳离子(C6+)的产生是非常重要的。用激光离子源可产生高强度、高电荷态(5+、6+)的碳离子。利用DPIS-RFQ聚束器直线加速器进行了C6+离子的加速实验，研制了加速能为2 MeV/u的APF-IH实验加速器，作为实际系统的1/3比例原型。2004年10月，APF-IH直线加速器将小电流质子加速到2 MeV。因此，在NIRS重离子肿瘤治疗系统的推广项目中，采用了RFQ直线加速器和APF-IH加速器相结合的方案。类似的项目正在德国海德堡进行。

A RFQ linear accelerator (linac) with Direct Plasma Injection Scheme(DPIS) has been studied to accelerate high intense heavy ion beam for injector of compact cancer therapy system. The DPIS-RFQ buncher linac was designed to confirm characteristics of carbon ions acceleration. Its operating frequency is 100 MHz. The beam test stand with the DPIS-RFQ linac and a CO2 laser ion source was fabricated at National Institute Radiological Science(NIRS). We succeeded to accelerate carbon ions beam of 50mA with the system and established an international record in July 2004. The results were reported in some conferences : International Linear Accelerator conference (Linac2004) in Germany and Particle Accelerator Society in Japan. In order to realize compact heavy ion cancer therapy system the production of full striped carbon ion (C6+) is important. High intense and higher charge state (5+,6+) carbon ions can be produced with a YAG laser ion source. Acceleration test of C6+ ion with the DPIS-RFQ buncher linac has been carried out.An APF-IH test linac of acceleration energy 2 MeV/u was developed as the 1/3 scale prototype of real system. The APF-IH linac was accelerated low current proton up to 2 MeV in October 2004. As a result, the combination of RFQ linac and APF-IH linac was adopted in popularization project of heavy ion cancer therapy system at NIRS. Similar project of is in progress at Heidelberg in Germany.