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Supernova Neutrino Detection: OMNIS |
Supernovae are the most energetic events ever observed in our Galaxy (believed to occur roughly every 10-30 years). A core collapse supernova explodes with about roughly 1000 times the total energy output of our Sun over its entire 10-billion-year lifetime, but in a period of only about 10 seconds. Some 99% of the energy released from a supernova is in the form of neutrinos, elusive sub-atomic particles that rarely interact with normal matter. Only about 1% of the energy release goes into the explosion itself, and only about 1% of that is finally released as light....which is still enough to make a supernova as bright as an entire galaxy for a brief time.
In 1987, a supernova was observed in the Large
Magellanic Cloud, and for the first, and as yet only time, neutrinos from beyond our galaxy were unambiguously detected. Only about 20 neutrino events were detected from this distant explosion (~170,000 light years from Earth), but even those were enough to confirm the basic concepts of core collapse supernova.
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In 1990, researchers described the use of salt deposits as a neutrino to neutron converter. They reasoned that if a neutron detector was installed deep in a salt mine, then the expanding neutrino front from an exploding supernova would produce a burst of neutrons as it passed through the salt. These neutrons could then be used to derive signatures of supernova phenomena, such as its collapse rate and the poorly understood nuclear reactions that create the heavy elements of our universe. |
Over the last decade, these researchers have modified their detector concepts, but they still intend to make measurements of such a neutrino burst from a distant supernova in the salt mine at the Waste Isolation Pilot Plant
(WIPP). The OMNIS collaboration is considering installing a prototype neutrino detector to
capture a supernova in our galaxy as its wave of neutrinos passes through the underground drifts at
WIPP. OMNIS stands for "Observatory for Multi-flavor NeutrInos from Supernovae".
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The prototype detector is named OMNISita (colloquial Spanish for "little OMNIS"). The collaboration maintains its own web site, which contains much more information about supernovae and the OMNIS project. | |
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Click here to see the proposed OMNISita detector prototype location in the WIPP underground.... |
OMNIS and OMNISita will be detectors that use a novel technique to observe many more neutrinos than were seen in the 1987 supernova, especially the muon and tau neutrino flavors. |
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With these data, detailed comparisons of flux, energy and arrival time with current theory could be made, helping to resolve many of the uncertainties that remain. The vast distances involved may allow many aspects of fundamental neutrino physics to be studied, such as neutrino mass, the first tantalizing glimpse of physics beyond the standard model. | |
