Polarized jets and storage cell targets for storage rings

The state of the art of polarized gas targets for storage rings is reviewed. The storage cell technique is inevitable for producing densities with sufficient luminosity for electron scattering experiments. Different sources, of polarized, atoms for jets and storage cell targets are compared. Remarkable progress has been achieved over the last 15 years, which has led to a vast amount of experimental results with. high statistics and good systematic precision. For hydrogen or deuterium gas targets based on atomic beam sources and cold storage cells an areal density of 10(14) atoms/cm(2) with high polarization has been achieved. For a next generation experiment this figure could be considerably enhanced.