  We study light coherent transport in the weak localization regime using
magneto-optically cooled strontium atoms. The coherent backscattering cone is
measured in the four polarization channels using light resonant with a J=0 to
J=1 transition of the Strontium atom. We find an enhancement factor close to 2
in the helicity preserving channel, in agreement with theoretical predictions.
This observation confirms the effect of internal structure as the key mechanism
for the contrast reduction observed with an Rubidium cold cloud (see: Labeyrie
et al., PRL 83, 5266 (1999)). Experimental results are in good agreement with
Monte-Carlo simulations taking into account geometry effects.
