High Z Droplets -- A Novel Source of Heavy Ions for Nuclear Physics

79298S A proposed next-generation facility to accelerate and collide rare isotopes of heavy elements for basic research into nuclear physics and astrophysics has become a high priority for the DOE. Present ion sources, based on electron cyclotron resonance techniques, cannot produce the necessary beam current for many of these rare isotopes. New ways to significantly increase the beam current, as well as the charge state of the generated ions, are required for many different heavy elements. It has been shown that laser ionization of micron-sized, tin-doped water droplets can generate mass-limited plasmas that can effectively produce extreme UV light for chip lithography, accelerated ions for radiography, and x-rays. In this process, the droplet and laser parameters can be tuned to ionize the precisely controlled number of tin atoms (or other heavy elements) to the same charge state, which can be quite high. This project will first assess and later demonstrate the suitability of this "laser droplet plasma" technology for the enhancement of existing rare isotope ion sources, or for the development of new sources. In Phase I, particle-in-cell simulations of a laser droplet plasma will be used to assess the resulting enhancement of high charge state ions of relevant rare isotopes. Parallel simulations of micro-droplet irradiation by higher-intensity laser pulses, and the resulting acceleration of heavy ions, will be used to explore the possibility of developing a completely novel rare isotope ion source. Commercial Applications and Other Benefits as described by the awardee: The technology should provide dramatic benefits to the proposed next-generation facility to accelerate and collide rare isotopes of heavy elements for basic research. In the process, a commercial particle-in-cell code will be significantly enhanced, leading to increased sales. Also, the simulation expertise developed for laser droplet plasmas should have application in the area of plasma source development for extreme UV lithography.