Shock launching in silicon studied with use of pulsed x-ray diffraction

Multikilobar shocks were launched into a single crystal of (111) silicon coated with 1000 A{} of aluminum and a 25-{μ}m transparent plastic layer by irradiation with a 1-nsec pulse of 1.06-{μ}m laser light at 0.8--8 J cm^-2. Peak lattice compressions were directly measured and shocked-lattice stresses inferred as a function of irradiance and time by Bragg-diffracting a short (<100 psec) burst of probing x rays through the shock-launching region. Compressions of up to {~}4% were measured, corresponding to stresses of the order of 70 kbar, at irradiances of {~}4×{}10⁹ W cm^-2.