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A cold electron target with a cryogenic GaAs-photocathode electron source was developed for the Heidelberg Test Storage Ring. Two independent electron facilities (cooler and target) allow to separate cooling of the ion beam from target operation improving the quality of electron and ion beams. In addition a strong gain in the resolution was achieved with a help of a cryogenic photoelecron source providing dc electron currents up to 0.5 mA with an emission energy spread of about 10 meV. In first recombination measurements at the target, performed on HD +, H3+ and Sc18+, low energy resonant structures at milli-eV collision energies revealed unprecedented low transverse and longitudinal electron temperatures of about 0.5 meV and 0.025 meV, respectively. The photocathode source will be also used to provide cold beams for electron cooling of low-energy ions stored at the electrostatic Cryogenic Storage Ring which will be built at MPIK. The perspectives of photocathode-driven electron coolers operating at very low laboratory energies are discussed. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]