Entwicklung von großvolumigen CdTe und (Cd Zn)Te Detektorsystemen Zusammenfassung: Interest in CdTe and (Cd Zn)Te as a detector material for gamma radiation has risen in the last two decades. Good spectroscopic properties and the possibility to use CdTe and (Cd Zn)Te at room temperature increased demand for large volume detector systems. Among other areas Detectors with large volume are needed for the planned upgrade of the Ortsdosisleistungs Messnetz (ODL). This local dose radiation monitoring network consisting of approximately 1800 Geiger Müller tubes is used to measure radioactive background radiation across Germany. Individual nodes will be equipped with a spectroscopic system based on (Cd Zn)Te detectors. REWARD on the other hand aims for a mobile network that can be used for the identification and localization of radioactive sources. However the production of (Cd Zn)Te suffers from low yield due to defects. This means that only a limited amount of material is available for detector fabrication. At the same time device cost increases dramatically with detector volume. Building a large volume out of several smaller detectors is a cost efficient solution to both problems. Detecting and processing coincident events unifies these individual detectors into the combined volume of one larger detector