Assembly of the Majorana Demonstrator Module 1 detectors. Twenty-nine detectors are arranged in seven strings and mounted in an ultra-low-radioactivity copper cryostat. The array is assembled inside a nitrogen-purged glovebox to avoid exposure to naturally occurring radon in the air. Credit: Image courtesy of Sanford Underground Research Facility
In 2014, the Majorana Demonstrator started its search for neutrinoless double beta decay. Observation of this decay would have profound implications for our understanding of physics, including providing hints as to how the Big Bang produced more matter than it did antimatter. The 1st of 2 modules, with >22 kg of high purity germanium detectors, has been turned on.
The Majorana experiment will search for neutrinoless double beta (0νββ) decay in germanium-76. Observation of this decay would have profound implications for our understanding of physics, by showing that lepton number conservation is violated, proving that the neutrino and the anti-neutrino are identical, and providing hints as to how the Big Bang produced more matter than it did antimatter.
Majorana uses detectors made from germanium enriched in the isotope 76Ge. In May 2015, the first full module containing 29 germanium detectors was installed in the lead/copper shield. A second module with another 30 detectors is currently being assembled and will be moved into the shield in late 2015. The Majorana Demonstrator (MJD) is located 4850 feet underground in the Sanford Underground Research Facility in Lead, SD. The deep location and an ultra-clean laboratory are required to eliminate “background” events that could be mistaken for the extremely rare 0νββ decays. The MJD project aims to demonstrate that extremely low background rates can be achieved, to prove the feasibility of a larger, more sensitive experiment proposed for the future.
http://science.energy.gov/np/highlights/2015/np-2015-09-c/
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