Horne S F, Silterra J, Holber W
Energetiq Technology, Inc; Woburn MA, 01801 USA.
J Phys Conf Ser. 2009;186:12028. doi: 10.1088/1742-6596/186/1/012028.
Soft X-rays (< 1Kev) are of medical interest both for imaging and microdosimetry applications. X-ray sources at this low energy present a technological challenge. Synchrotrons, while very powerful and flexible, are enormously expensive national research facilities. Conventional X-ray sources based on electron bombardment can be compact and inexpensive, but low x-ray production efficiencies at low electron energies restrict this approach to very low power applications. Laser-based sources tend to be expensive and unreliable. Energetiq Technology, Inc. (Woburn, MA, USA) markets a 92 eV, 10W(2pi sr) electrode-less Z-pinch source developed for advanced semiconductor lithography. A modified version of this commercial product has produced 400 mW at 430 eV (2pi sr), appropriate for water window soft X-ray microscopy. The US NIH has funded Energetiq to design and construct a demonstration microscope using this source, coupled to a condenser optic, as the illumination system. The design of the condenser optic matches the unique characteristics of the source to the illumination requirements of the microscope, which is otherwise a conventional design. A separate program is underway to develop a microbeam system, in conjunction with the RARAF facility at Columbia University, NY, USA. The objective is to develop a focused, sub-micron beam capable of delivering > 1 Gy/second to the nucleus of a living cell. While most facilities of this type are coupled to a large and expensive particle accelerator, the Z-pinch X-ray source enables a compact, stand-alone design suitable to a small laboratory. The major technical issues in this system involve development of suitable focusing X-ray optics. Current status of these programs will be reported.
软X射线（<1千电子伏特）在成像和微剂量测定应用方面都具有医学价值。这种低能量的X射线源带来了技术挑战。同步加速器虽然功能强大且灵活，但却是极其昂贵的国家研究设施。基于电子轰击的传统X射线源可以做到紧凑且廉价，但在低电子能量下X射线产生效率较低，这限制了这种方法仅适用于非常低功率的应用。基于激光的源往往既昂贵又不可靠。Energetiq技术公司（美国马萨诸塞州沃本）销售一种为先进半导体光刻开发的92电子伏特、10瓦（2π立体角）无电极Z箍缩源。该商业产品的一个改进版本在430电子伏特（2π立体角）下产生了400毫瓦，适用于水窗软X射线显微镜。美国国立卫生研究院已资助Energetiq公司设计和建造一台演示显微镜，该显微镜使用此源与聚光光学器件耦合作为照明系统。聚光光学器件的设计将源的独特特性与显微镜的照明要求相匹配，而显微镜的其他部分则采用传统设计。正在进行一个单独的项目，与美国纽约哥伦比亚大学的RARAF设施合作开发一种微束系统。目标是开发一种聚焦的亚微米束，能够向活细胞核输送>1戈瑞/秒的剂量。虽然大多数这种类型的设施都与大型且昂贵的粒子加速器相连，但Z箍缩X射线源能够实现适合小型实验室的紧凑、独立设计。该系统的主要技术问题涉及开发合适的聚焦X射线光学器件。将报告这些项目的当前状态。
