The Institut für Kernphysik of the Forschungszentrum Jülich GmbH has been designing and developing a new injector for the cooler synchrotron COSY. To reach the set goal, the projected linac injector will have to be equipped with new ion sources. One ion source will deliver unpolarized; the other polarized H− or D− pulsed beams in the mA range having an energy of 25 keV. Pulses of up to 500 μs in width and repetition rates up to 2 Hz are foreseen. Several arrangements of the ion sources and the low energy beam transport system have been investigated. The principles guiding the layout of the low energy beam transport are discussed. First operational results of the source for unpolarized H− and D− are discussed.