Research type | Particle physics, Astrophysics |
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Location | L'Aquila, Abruzzo, Italy 42°27′14″N 13°34′34″E / 42.454°N 13.576°E |
Operating agency | INFN |
Website | www |
The Cadmium Zinc Telluride 0-Neutrino Double-Beta (COBRA) experiment is a large array of cadmium zinc telluride (CdZnTe) semiconductors searching for evidence of neutrinoless double beta decay and to measure its half-life. COBRA is located underground, within the Gran Sasso National Laboratory. The experiment was proposed in 2001, and installation of a large prototype began in 2006.[1]
COBRA is designed to prove the validity of the CdZnTe detection technique.[2] The initial setup of the experiment, in 2007, was an array of four 1-cm3 CdZnTe semiconductors.[3] 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.[4] 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.[4]
As of 2016, COBRA had collected about 250 kg days of calibrated exposure.[2] Efforts were focused on reducing the background readings in order to increase the sensitivity of the experiment.[4]
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