  We report on the design and first results from experiments looking at the
formation of radiative shocks on the Shenguang-II (SG-II) laser at the Shanghai
Institute of Optics and Fine Mechanics in China. Laser-heating of a two-layer
CH/CH-Br foil drives a $\sim$40 km/s shock inside a gas-cell filled with argon
at an initial pressure of 1 bar. The use of gas-cell targets with large
(several mm) lateral and axial extent allows the shock to propagate freely
without any wall interactions, and permits a large field of view to image
single and colliding counter-propagating shocks with time resolved,
point-projection X-ray backlighting ($\sim20$ $\mu$m source size, 4.3 keV
photon energy). Single shocks were imaged up to 100 ns after the onset of the
laser drive allowing to probe the growth of spatial non-uniformities in the
shock apex. These results are compared with experiments looking at
counter-propagating shocks, showing a symmetric drive which leads to a
collision and stagnation from $\sim$40 ns onward. We present a preliminary
comparison with numerical simulations with the radiation hydrodynamics code
ARWEN, which provides expected plasma parameters for the design of future
experiments in this facility.
