Development of NbTi CCT superconducting magnet technology for radiotherapy applications

最先进的粒子放射治疗设备得益于超导（SC）磁体技术，使其尺寸显著减小。这在下一代离子治疗系统中尤为重要，下一代离子治疗系统将向患者提供碳离子束，并将显著扩大提供给患者的治疗范围；通过使用超导磁体，利用工业上成熟的铌钛电缆技术，可以将现有粒子源的尺寸从80米缩小到25米，产生约5T的磁场。然而，目前还没有合适的超导磁体原型设计。本项目的目的是在具有大（>80mm）中心孔径的弯曲低温恒温器中开发一种新型的斜余弦- θ (CCT)组合函数（CF）偶极子。本研究的第一个目标将应用于紧凑型同步加速器，利用高度新颖的混合快速循环设计，这是以前没有提出的；快速循环紧凑型C6+同步加速器将通过在患者的不同治疗深度提供高剂量率和快速，精确的剂量递送变化来实现治疗的阶梯式变化。开发合适的CF磁体是该项目的关键推动因素，该项目将为欧洲提供下一代离子治疗系统，并已被英国确定为未来所需的治疗设施。其他应用包括使用类似的技术进行最终剂量输送，以及用于x射线成像科学的粒子源的其他应用。我们将与CERN超导磁体设计组和STFC Daresbury实验室/墨尔本大学的项目合作伙伴合作，利用我们之前在CCT设计方面的经验，开发一种弯曲的（90度）偶极/四极磁体，在单个超低温旋转低温恒温器中具有交替梯度聚焦；这是以前没有做过的。欧洲核子研究中心的合作将提供他们在绕组和组装类似磁铁系统方面的广泛工程知识，我们打算在博士期间制作一个候选磁铁的原型。后来的选择包括使用替代导体材料，如NbSn和REBCO，以实现更大孔径的磁铁。将这项技术转化为英国工业还有很大的空间。几家英国公司在核磁共振磁体系统等领域已有SC生产，我们将探索与合适供应商的合作伙伴关系，期待稍后在英国建造离子处理设施。

Start-of-the-art particle radiotherapy facilities benefit from superconducting (SC) magnet technology to allow a significant reduction in their size. This is particularly important in the next generation of ion therapy systems that will deliver carbon-ion beams to patients and will significantly expand the range of treatments offered to patients; present-generation particle sources can be reduced from c.80m to c25m in size by using superconducting magnets utilizing industrially-proven niobium-titanium cable technology delivering fields around 5T. However, no suitable design of superconducting prototype magnet has yet been demonstrated.This project aims to develop the science and engineering of a novel canted-cosine-theta (CCT) combined-function (CF) dipole in a curved cryostat with large (>80mm) central aperture. The first aim of this study will be applied to a compact synchrotron utilizing a highly-novel hybrid rapid cycling design that has not been previously proposed; a rapid-cycling compact C6+ synchrotron would deliver a step change in therapy by delivering both high dose rates and rapid, precise variation of the dose delivery at different treatment depths in patients. The development of a suitable CF magnet is the key enabler for this project, which would deliver the next-generation of ion therapy system to be applied in Europe, and which has been identified in the UK as a future needed treatment facility. Other applications include use of similar technology for the final dose delivery, and for other applications in particle sources for x-ray imaging science.Working with our project partners in the CERN superconducting magnet design group and at STFC Daresbury Laboratory/University of Melbourne, we will use our previous experience of CCT design to develop a curved (90-degree) dipole/quadrupole magnet with alternating-gradient focusing in a single cryo-cooled rotating cryostat; this has not previously been done. CERN collaboration will provide their extensive engineering knowledge of winding and assembling similar magnet systems, and we intend to prototype a candidate magnet during the PhD duration. Later options include the use of alternative conductor materials such as NbSn and REBCO to achieve larger aperture magnets.There is significant scope to translate the technology into UK industry. Several UK companies have existing SC production in areas such as MRI magnet systems, and we will explore partnerships with suitable suppliers to look forward to later construction of a UK ion treatment facility.