  Possible parameters of Light Sources (LS) based on Backward Rayleigh
Scattering (BRS) of laser photons on relativistic ion beams in storage rings
are discussed. It was shown that the parameters of the LS based on the RHIC
storage ring (dedicated to High Energy Physics now) satisfy the requirements of
the 2d generation LS. Using the ordinary or enhanced radiative cooling of ion
beams in storage rings by broad-band lasers will permit to decrease essentially
their emittance, dimensions, angular and energy spreads and convert them to the
next generation of LS.
