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Research to built a compact system to shape irradiation field for the particle cancer therapy

研究建立紧凑的系统来塑造粒子癌症治疗的照射场

基本信息

批准号：
18390334
负责人：
HATANAKA Kichiji
金额：
$ 11.12万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

In order to build a compact irradiation system for the particle cancer therapy, we fabricated a magnet to scan the beam in a plane perpendicular to the beam axis. The magnet consists of two sets of air core coils. We used the high temperature superconducting wire of the material Bi2223 which has a large margin in operating temperature. In the design, numerical analyses were performed on the magnetic fields, the cooling system and supporting frame against the electromagnetic force. Coils showed superconductivity in10 hours by conduction cooling with a single stage GM cooler. Critical currents of coils were measured to be higher than 250A at 20K as expected. No damages were observed during winding. Magnetic field was measured along the center line of each coil. The results agreed very well with the numerical calculations. An alternating current (AC) power supply was constructed with an inverter, an induction motor and a generator. Coils were excited in series with condensers. The AC power loss of coils was measured at 10, 15 and 20 Hz. The power loss per cycle is independent of the frequency. This shows the loss is the hysteretic one which is characteristic to high temperature superconductors. The loss shows 2.4^<th> power dependence on exciting currents. This phenomenon is same as that reported for low magnetic field cables. There have been few reports on the AC loss studies at high magnetic fields. Present results give the invaluable information towards future applications in cancer therapy systems, accelerators, etc.

为了建立一个紧凑的照射系统的粒子治疗癌症，我们制造了一个磁铁扫描束在一个平面垂直于束轴。磁体由两组空心线圈组成。我们使用的高温超导导线材料Bi 2223，它具有一个大的幅度在工作温度。在设计中，对磁场、冷却系统和支撑框架的电磁力进行了数值分析。用单级GM冷却器进行传导冷却，线圈在10小时内显示出超导性。在20K时，线圈的临界电流大于250A。缠绕过程中未观察到损坏。沿每个线圈的中心线沿着测量磁场。计算结果与数值计算结果吻合得很好。交流电源由逆变器、感应电动机和发电机组成。线圈与冷凝器串联励磁。在10、15和20 Hz下测量线圈的交流功率损耗。每个周期的功率损耗与频率无关。这表明损耗是高温超导体特有的滞后损耗。损耗显示2.4^<th>功率依赖于激励电流。这种现象与低磁场电缆的报道相同。在高磁场下的交流损耗研究报道很少。目前的结果提供了宝贵的信息，对未来的应用在癌症治疗系统，加速器等。