COBRA Experiment

Set up

COBRA is designed to prove the validity of the CdZnTe detection technique. The initial setup of the experiment, in 2007, was an array of four 1-cm³ CdZnTe semiconductors. This was then upgraded to 64 detectors in a 4×4×4 array. The CdZnTe crystals act as both the detector and source material, as nine of the isotopes in this material are double beta decay candidates. The location of the experiment allows for shielding from external gamma rays; to this end, the detectors are also shielded by 5 cm of radiopure electrolytic copper and 20 cm of low-radioactivity lead. 7 cm of boron-loaded polyethylene shields the experiment against neutrons, and the experiment is constantly flushed with nitrogen gas to prevent contamination with radon.