Randers-Pehrson Gerhard, Johnson Gary W, Marino Stephen A, Xu Yanping, Dymnikov Alexander D, Brenner David J
Center for Radiological Research, Columbia University, New York,, NY 10032, USA.
Nucl Instrum Methods Phys Res A. 2009 Oct 11;609(2):294-299. doi: 10.1016/j.nima.2009.08.041.
A lens system consisting of two electrostatic quadrupole triplets has been designed and constructed at the Radiological Research Accelerator Facility (RARAF) of Columbia University. The lens system has been used to focus 6-MeV (4)He ions to a beam spot in air with a diameter of 0.8 µm. The quadrupole electrodes can withstand voltages high enough to focus (4)He ions up to 10 MeV and protons up to 5 MeV. The quadrupole triplet design is novel in that alignment is made through precise construction and the relative strengths of the quadrupoles are accomplished by the lengths of the elements, so that the magnitudes of the voltages required for focusing are nearly identical. The insulating sections between electrodes have had ion implantation to improve the voltage stability of the lens. The lens design employs Russian symmetry for the quadrupole elements.
哥伦比亚大学放射研究加速器设施（RARAF）设计并建造了一个由两个静电四极三联体组成的透镜系统。该透镜系统已被用于将6兆电子伏特的氦离子聚焦到空气中直径为0.8微米的束斑上。四极电极能够承受足够高的电压，以聚焦高达10兆电子伏特的氦离子和高达5兆电子伏特的质子。四极三联体设计新颖之处在于，通过精确构建实现对准，并且四极的相对强度由元件的长度来实现，从而使聚焦所需的电压大小几乎相同。电极之间的绝缘部分进行了离子注入，以提高透镜的电压稳定性。透镜设计采用了四极元件的俄罗斯对称结构。
