Plasma Science: From Fundamental Research to Technological Applications (1995)
Chapter: PLASMA ISOTOPE SEPARATION
technology by increasing the efficiencies of lasers from a fraction of a percent to 10%. This improvement was particularly dramatic in excimer lasers. Examples include the rare-gas lasers that radiate in the vacuum ultraviolet (VUV), the rare-gas halide lasers that lase in the ultraviolet (UV), the rare-gas triatomic excimers that have broadband emission in the visible, and the metal excimers that emit in the visible and UV.
Gas lasers have produced many important technological capabilities. Examples include optical lithography, where rare-gas fluoride lasers have extended the resolution to less than 0.5 µm; laser working of metals, where high power CO2 lasers are now used routinely for welding, cutting, and marking in industry; and medicine, where lower-power gas lasers have made a significant impact, including the use of surgical CO2 lasers and excimer lasers for treating eyes and occluded arteries.
The combined gas laser market is presently of the order of $300 million and is predicted to grow at an annual rate of approximately 5%. There are also other emerging uses for these lasers, such as LIDAR (laser radar) for airports that can measure the location of wind shear and thereby increase the safety of air travel, and laser-produced x-ray sources for microlithography.
PLASMA ISOTOPE SEPARATION
Funding for plasma isotope separation has decreased dramatically in the post-Cold War era. Isotope separation has been actively investigated for the last 20 years, principally by plasma centrifuge, laser (AVLIS), and ion cyclotron resonance techniques. Of these methods, the AVLIS program at Lawrence Livermore National Laboratory has been the most strongly supported. The results are classified. Briefly, the separation process involves the selective ionization of one isotope and the subsequent collection of this ion. Lasers are used to ionize the desired isotopes, which form a low-temperature plasma. Plasma physics issues that have to be addressed include excited and ionic species reactions, homogeneous chemistry, and the physics and chemistry of the sheath near the collection electrodes. More conventional plasma isotope separation has been investigated on a much smaller scale by several groups including the FOM Institute for Plasma Physics in the Netherlands, Yale University, the Max Planck Institute in Germany, the Sydney University School of Plasma Physics in Australia, the National Space Research Institute in Brazil, and TRW in the United States.
There are important uses of isotope separation besides nuclear fuels enrichment, including medical diagnostics, chemistry, and basic research. Thus, the development of plasma centrifuge technology offers a number of potential opportunities. The demand for stable, enriched isotopes for medical applications grows each year. The plasma centrifuge offers an improved means of meeting this need. However, at present, many important basic plasma phenomena remain
