1. Materials Science and Engineering Division, Material Measurement Laboratory, NIST; 100 Bureau Drive Gaithersburg MD 20899-8541 USA
2. Semiconductor and Dimensional Metrology Division, Physical Measurement Laboratory, NIST; 100 Bureau Drive Gaithersburg MD 20899-8120 USA
3. Department of Electrical Engineering; Penn State University University Park; PA 16802 USA
4. Institute of Computational Physics; Zurich University of Applied Sciences, ZHAW; Technikumstrasse 9 8401 Winterthur Switzerland
5. Department of Electrical and Computer Engineering; Old Dominion University; Norfolk VA 23529 USA