OPTIMIZATION OF PIN-FIN ARRAYS FOR HELIUM-COOLED FINGER-TYPE DIVERTOR J. D. Rader / B. H. Mills / D. L. Sadowski / M. Yoda / and S. I. Abdel-Khalik G. W. Woodruff School of Mechanical Engineering / Karlsruhe Research Center / U.S. DOE / Georgia Institute of Technology / Atlanta / /