Papers by Author: Ian G. Brown

Abstract: Vacuum arc plasma can be formed using particularly uncomplicated hardware, providing a means for laboratory scale formation of dense and highly-ionized metal plasma. The simplicity and versatility of the approach has led to its widespread use in recent times for both fundamental and technological applications. When embodied in a plasma gun configuration, the source can provide a valuable tool for plasma deposition of metal and metal-containing thin films, including in plasma immersion configurations. When embodied in an ion source configuration, high current beams of metal ions can be formed, and such beams have found good use for ion implantation and particle accelerator injection. Here we briefly review vacuum arc plasma guns and ion sources, outlining some of the hardware embodiments that have been developed at Berkeley and used for various materials modification applications.

Abstract: The interaction between ion beam and biological cells has been studied to apply ionbeam- induced mutation to breeding of crops and gene transfer in cells. Formation of micro-craters has been observed after ion bombardment of plant cells and they are suspected to act as pathways for exogenous macromolecule transfer in the cells. A technique of in-situ atomic force microscopy (AFM) in the ion beam line is being developed to observe ion bombardment effects on cell surface morphology during ion bombardment. A commercial AFM is designed to place inside the target chamber of the bioengineering ion beam line at Chiang Mai University. In order to allow the ion beam to properly bombard the sample without the risk of damaging the scanning tip and affecting normal operation of AFM, geometrical factors have been calculated for tilting the AFM with 35 degree from the normal. In order to avoid vibrations from external sources, mechanical designs have been done for a vibration isolation system. Construction and installation of the in-situ AFM facility to the beam line have been completed and are reported in details.