  We argue that the process gamma +A \to J/psi + gap + X at large momentum
transfer provides a quick and effective way to test onset of a novel
perturbative QCD regime of strong absorption for the interaction of small
dipoles at the collider energies. We find that already the first heavy ion run
at the LHC will allow to study this reaction with sufficient statistics via
ultraperipheral collisions hence probing the interaction of q\bar q dipoles of
sizes ~ 0.2 fm with nuclear media down to x ~ 10^{-5}.
