A novel experimental sandwich arrangement of molybdenum thin sheets and wires was shock‐loaded at a pressure of 150 kbar (for 2 &mgr;sec), and thin foils and emission end forms prepared from these samples were simultaneously examined by transmission electron and field‐ion microscopy, respectively. Dislocation loop densitis were observed to be 5×109cm−3in the annealed foil samples as compared with 4×1014cm−3in the shock‐loaded foil samples, and 75% of the loop types analyzed were vacancy. The direct measurement of vacancy density in the field‐ion microscope revealed twice as many vacancies (including aggregates) in the shock‐loaded wires as compared with the annealed unshocked wires.