The Columbia University sub-micron charged particle beam

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• 作者：Gerhard R ; ers-Pehrson ; Gary W. Johnson ; Stephen A. Marino ; Yanping Xu ; Alex ; er D. Dymnikov ; David J. Brenner
• 关键词：Microbeam ; Quadrupole ; Electrostatic ; Sub-micron ; Charged particle beam
• 刊名：Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
• 出版年：2009
• 出版时间：11 October 2009
• 年：2009
• 卷：609
• 期：2-3
• 页码：294-299
• 全文大小：406 K

文摘

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 ⁴He ions to a beam spot in air with a diameter of 0.8 μm. The quadrupole electrodes can withstand voltages high enough to focus ⁴He 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.