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]
| Research type | Particle physics, Astrophysics |
|---|---|
| Location | L'Aquila, Abruzzo, Italy 42°27′14″N 13°34′34″E / 42.454°N 13.576°E |
Operating agency | INFN |
| Website | www |
Set up
editCOBRA 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]
Results
editAs 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]
References
edit- ^ Wilson, J. R. (2008). "The COBRA experiment". Journal of Physics: Conference Series. 120 (5): 052048. doi:10.1088/1742-6596/120/5/052048. ISSN 1742-6596.
- ^ a b Ebert, J.; et al. (2016-01-21). "The COBRA demonstrator at the LNGS underground laboratory". Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 807: 114–120. arXiv:1507.08177. Bibcode:2016NIMPA.807..114E. doi:10.1016/j.nima.2015.10.079. ISSN 0168-9002. S2CID 110688200.
- ^ Bloxham, T.; et al. (2007-08-03). "First results on double β-decay modes of Cd, Te, and Zn Isotopes". Physical Review C. 76 (2): 025501. arXiv:0707.2756. Bibcode:2007PhRvC..76b5501B. doi:10.1103/PhysRevC.76.025501. S2CID 119257817.
- ^ a b c Ebert, J.; et al. (2013). "Current Status and Future Perspectives of the COBRA Experiment". Advances in High Energy Physics. 2013: 1–6. doi:10.1155/2013/703572. ISSN 1687-7357.