Number 198 (Story #2), October 12, 1994 by Phillip F. Schewe and Ben Stein PERHAPS THE MOST CHEMICALLY ACTIVE FORM OF MATTER IN NATURE are the bare uranium (U92+) ions recently made by scientists at Lawrence Livermore National Laboratory (see Update #185). The electrical attraction between such a heavy ion and electrons on surfaces is immense. The Livermore researchers (contact Ross Marrs, 510-422-3890) invented a tabletop device known as the electron beam ion trap (EBIT) to make U92+ and many other highly charged ions such as Xe44+. Although EBIT was originally developed for trapping heavy ions, its mode of operation can be modified to provide an efficient source of very slow, very highly charged ions for collisions with surfaces. For instance, single-ion impacts on insulators have led to the creation of nm-sized blister-like defects. The volume of the defects can be controlled by varying the charge of the incident ion. These properties may eventually lead to applications in nanotechnology such as extremely high-density data storage, nanoscale electronic circuit patterns, and micromachining. (Physics Today, October 1994.)