Goodhead D T, Bance D A
Phys Med Biol. 1984 May;29(5):535-41. doi: 10.1088/0031-9155/29/5/006.
Very low energy ( ultrasoft ) x-rays of 0.3-5 keV have provided a unique tool for investigation of mechanisms of radiation action, especially with respect to the energy and spatial properties of critical radiation damage in mammalian cells. Experimental investigations to date have been partially limited by the availability and characteristics of suitable ultrasoft x-ray sources. The suitability of small electrostatic proton accelerators, such as exist in many laboratories, have been investigated as a means of producing a secondary beam of ultrasoft x-rays suitable for irradiation of biological and biochemical systems. Results are presented on the physical characteristic of carbon K (0.28 keV) and aluminium K (1.5 keV) ultrasoft x-ray beams produced by bombardment of solid targets of carbon and aluminium with protons of energies up to 750 kV and currents up to 500 microA. These characteristics are compared with those of a cold cathode discharge ultrasoft x-ray tube previously used for mammalian cell investigations. It is seen that the proton accelerator produces much more versatile beams of characteristic ultrasoft x-rays which greatly extend the scope for future experiments on mammalian cells, micro-organisms and biochemical systems. Nevertheless there are situations in which the cold-cathode discharge tube will remain the source of choice and there are other situations, requiring for example energies between characteristic lines, where the greatly more complex synchrotron radiation sources are required.
能量在0.3至5千电子伏的极低能量（超软）X射线为研究辐射作用机制提供了一种独特工具，尤其是在研究哺乳动物细胞中关键辐射损伤的能量和空间特性方面。迄今为止，实验研究部分受到合适超软X射线源的可用性和特性的限制。人们已对许多实验室中现有的小型静电质子加速器作为产生适用于照射生物和生化系统的超软X射线次级束的手段进行了研究。文中给出了用能量高达750千伏、电流高达500微安的质子轰击碳和铝的固体靶所产生的碳K（0.28千电子伏）和铝K（1.5千电子伏）超软X射线束的物理特性。将这些特性与先前用于哺乳动物细胞研究的冷阴极放电超软X射线管的特性进行了比较。可以看出，质子加速器能产生用途更为广泛的特征超软X射线束，这极大地扩展了未来对哺乳动物细胞、微生物和生化系统进行实验的范围。然而，在某些情况下，冷阴极放电管仍将是首选的光源，而在其他一些情况下，例如需要特征线之间的能量时，则需要更为复杂的同步辐射源。
