摘要
目的本文通过分析瓦里安2300CD加速器的一例偏转电源隐性故障,探讨瓦里安高能加速器的能量稳定机制以及该类加速器偏转系统的维护维修方法。方法从机器物理和电子工程双重角度,系统分析瓦里安C-系列高能直线加速器的偏转磁铁构成、偏转电流的编程机制以及机内监测连锁机制、金属线圈的电阻温度效应、偏转电源的阻抗匹配。归纳总结偏转系统机器物理方面的难点以及易被疏忽之处。结果偏转系统不仅是能量筛选机构而且也是能量稳定机制,能量的轻微变化即可导致剂量学对称性外显参数的较大偏差,对称性合标则能量一定合标。校准检查序列和关断导向伺服可将剂量学连锁从剂量学故障中排除。暂停水冷机试验可以判断偏转线圈是否超温。结论 BMAG连锁属于冗余设置,即使偏转系统出现隐性故障,对称性连锁能屏障剂量学风险。
Objective By means of analyzing one covert fault of bend magnet power supply of Varian 2300 CD linear accelerator, this paper aims to discuss the energy stabilization mechanisms of Varian high energy linear accelerator and the maintenance methods of the bend magnet system. Methods This paper expounded the bend magnet constitution of Varian C-series high energy linear accelerators systematically from twofold view of machine physics and electronics engineering, the programming mechanisms of bend magnet current and the in-box monitor interlock mechanisms, the resistance temperature effect of mental coil, the impedance matching of bend magnet power supply. Conclusion and summary of the difficult and forgettable points of bend magnet machine physics were made. Results The bend magnet system was not only the energy filter but also the energy stabilization mechanism, the slight variation of energy could lead more deviation of overt symmetry, if the symmetry was not out of limits the energy no doubt conforms to the standards. The CAL/CHECK sequence and turn-off steering servo could get rid of dosimetry system fault from symmetry interlocks. Suspends chiller could determine the coils whether or not are over temperature. Conclusion The interlock BMAG is a redundant configuration, even if it occurs covert fault of bend magnet system, the interlocks of symmetry are protective screen of dosimetry risks.
引文
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