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Topic: Sudbury Neutrino Observatory


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In the News (Sat 23 Mar 19)

  
  Solar neutrino problem - Wikipedia, the free encyclopedia
The solar neutrino problem was a major discrepancy between measurements of the neutrinos flowing through the Earth and theoretical models of the solar interior, lasting from the mid-1960s to about 2002.
The solar neutrino problem was troubling because it meant that either general relativity was incorrect, models of stellar evolution were incorrect, or the Standard Model was incorrect.
The supernova 1987A produced an indication that neutrinos might have mass, because of the difference in time of arrival of the neutrinos detected at Kamiokande, and the small number detected versus the convective overturn model of supernovae.
en.wikipedia.org /wiki/Solar_neutrino_problem   (1059 words)

  
 Neutrino - Wikipedia, the free encyclopedia
A practical method for investigating neutrino masses (that is, flavour oscillation) was first suggested by Bruno Pontecorvo in 1957 using an analogy with the neutral kaon system; over the subsequent 10 years he developed the mathematical formalism and the modern formulation of vacuum oscillations.
Atmospheric neutrinos result from the interaction of cosmic rays with atoms in the Earth's atmosphere, creating showers of particles, many of which are unstable and produce neutrinos when they decay.
The first such use of neutrinos was proposed in the early 20th century for observation of the core of the Sun.
en.wikipedia.org /wiki/Neutrino   (3355 words)

  
 Sudbury Neutrino Observatory - Wikipedia, the free encyclopedia
SNO was the first solar neutrino detector capable of detecting all three neutrino flavours, and this capability is what allowed it to solve the solar neutrino problem.
The first measurements of the number of solar neutrinos reaching the earth were taken in the 1960s, and all experiments prior to SNO observed a third to a half fewer neutrinos than were predicted by the Standard Solar Model.
The Sudbury Neutrino Observatory is a major setting in the Neanderthal Parallax trilogy by Canadian science fiction author Robert J. Sawyer.
en.wikipedia.org /wiki/Sudbury_Neutrino_Observatory   (562 words)

  
 Neutrinos
The electron neutrino (a lepton) was first postulated in 1930 by Fermi to explain why the electrons in beta decay were not emitted with the full reaction energy of the nuclear transition.
Modern neutrino detectors at IMB in Ohio and Kamiokande in Japan detected neutrinos from Supernova 1987A.
New experimental evidence from the Super-Kamiokande neutrino detector in Japan represents the strongest evidence to date that the mass of the neutrino is non-zero.
hyperphysics.phy-astr.gsu.edu /hbase/particles/neutrino.html   (1421 words)

  
 SNO First Results
From this initial phase, the SNO scientists report on an accurate and specific measurement of the number of solar electron neutrinos reaching their detector, by studying a reaction unique to heavy water where a neutron is changed into a proton.
The Sudbury Neutrino Observatory is a unique neutrino telescope, the size of a ten-storey building, 2 kilometers underground in INCO's Creighton Mine near Sudbury Ontario planned, constructed and operated by a 100-member team of scientists from Canada, the United States and the United Kingdom.
The SNO detector consists of 1000 tonnes of ultra-pure heavy water enclosed in a 12-meter diameter acrylic plastic vessel, which in turn is surrounded by ultra-pure ordinary water in a giant 22-meter diameter by 34-meter high cavity.
www.sno.phy.queensu.ca /sno/first_results   (1065 words)

  
 Lab researcher to speak Thursday about SNO research findings | The Newsbulletin | June 11, 2002
But since the first results from SNO were presented in June 2001, it became apparent that the discrepancy was not caused by problems with any of the models of the sun, but rather that the neutrinos changed types as they traveled from their birthplace in the core of the sun across space toward the Earth.
The SNO detector, a 12-meter diameter acrylic plastic heavy-water-filled vessel, uses an array of 9,456 photomultiplier tubes to capture the tiny flashes of Cherenkov light that are created when the roughly 10 solar neutrinos per day that are stopped or scattered in the 1,000 tons of heavy water contained in the SNO detector.
Total neutrino count is determined by measuring the gamma rays generated when a deuteron in the heavy-water —; the hydrogen atoms have an extra neutron in their nucleus — is broken releasing a neutron and energy that results in the production of a gamma ray.
www.lanl.gov /orgs/pa/newsbulletin/2002/06/11/text02.shtml   (1026 words)

  
 The SNO Detector
The Sudbury Neutrino Observatory (SNO) is a new facility that has been constructed in Canada by a team of scientists from Canada, the United States and Britain.
Although the reaction is sensitive to all neutrino flavours, the electron-neutrino dominates by a factor of six.
The Sudbury basin is believed to be the remnants of a crater formed millions of years ago due to the impact of a massive meteor.
www.sno.phy.queensu.ca /sno/sno2.html   (3875 words)

  
 CERN Courier - The Sudbury Neutrino Observa - IOP Publishing - article
Today the Sudbury basin is circled with the world's largest concentration of nickel mines and in one of them, scientists accompany the miners on their morning descent to the 6800 ft (2000 m) level.
The Creighton mine in Sudbury - among the deepest in the world - was quickly identified as an ideal place for Chen's proposed experiment to be built and the SNO collaboration held its first meeting in 1984.
SNO's data-acquisition system, normally running at around 10 Hz, is set up to buffer several hundred events in a window lasting just a few seconds if necessary, and it also alerts the shift crew whenever the event rate rises significantly.
www.cerncourier.com /main/article/41/10/18   (1510 words)

  
 Office of Science - Feature Articles   (Site not responding. Last check: 2007-10-08)
Shown here under construction, the heart of the Sudbury Neutrino Observatory is a sphere 12 meters in diameter, surrounded by almost 10,000 photomultiplier tubes to catch the faint flashes of Cerenkov radiation that mark the passage of neutrinos through the heavy water filling the sphere.
In June of 2001, the SNO collaboration reported results from its first year of operations that, in combination with experimental data from the Super-Kamiokande neutrino detector in Japan, indicated with greater than 99-percent certainty that neutrinos change type or, as physicists say, "flavor," on their way here from the sun.
The Sudbury Neutrino Observatory is supported, in part, by the Department of Energy's Office of High Energy and Nuclear Physics within the Office of Science.
www.er.doe.gov /scweb/Science_News/feature_articles_2002/May/SNO_case/PF_SNO.htm   (1153 words)

  
 Sudbury neutrino observatory
SNO is a collaboration involving more than 60 scientists from a dozen laboratories and universities in the United States, Canada, and the United Kingdom.
Its mission is to answer some of the most perplexing questions about neutrinos, the particles emitted from the sun and from supernovae that are so ghostlike, one could pass untouched through a wall of lead stretching from the earth to the moon.
The SNO detector, which is suspended in a vast pool of purified water, consists of the geodesic sphere, the photomultiplier tubes attached to it, and an acrylic vessel, inside the sphere, that is filled with 1,000 tons of heavy water (deuterium oxide or D2O).
www.lbl.gov /Science-Articles/Archive/sudbury-neutrino.html   (753 words)

  
 The SNO Homepage
The Sudbury Neutrino Observatory (SNO) is taking data that has provided revolutionary insight into the properties of neutrinos and the core of the sun.
SNO is a heavy-water Cherenkov detector that is designed to detect neutrinos produced by fusion reactions in the sun.
Neutrinos react with the heavy water (D2O) to produce flashes of light called Cherenkov radiation.
www.sno.phy.queensu.ca   (639 words)

  
 Science & Technology at Scientific American.com: Ask the Experts: Physics: What is a neutrino?   (Site not responding. Last check: 2007-10-08)
A neutrino is a subatomic particle that is very similar to an electron, but has no electrical charge and a very small mass, which might even be zero.
In this solar neutrino event, 75 of the 9,600 light sensors in the detector observed a photon of light.
Supernovae too are predominantly a neutrino phenomenon, because neutrinos are the only particles that can penetrate the very dense material produced in a collapsing star; only a small fraction of the available energy is converted to light.
www.sciam.com /askexpert_question.cfm?articleID=000C732C-3B0C-1C71-84A9809EC588EF21   (583 words)

  
 Visit to the Sudbury Neutrino Observatory
The neutrino detector consists of a ball of heavy water surrounded by a shell of regular water in which the detectors are arranged so as to cover almost the entire surface of the sphere.
When a neutrino hits and interacts with a deuteron, a very high-energy photon is released traveling in the same direction as the neutrino had been, which, in the vast majority of cases, is directly away from the sun, wherever the sun happens to be relative to the SNO.
In addition to the neutrino detectors, there's also an elaborate set of "neutral-current detector" rods mounted inside the tank, and I confess that I did not understand exactly what they were for and how they worked.
www.geometer.org /sno/sno.html   (2698 words)

  
 Sudbury Neutrino Observatory reports new measurements - thanks to Table Salt!   (Site not responding. Last check: 2007-10-08)
Two-thirds of the electron-type neutrinos produced by nuclear reactions in the core of the Sun are observed to change to muon- or tau-type neutrinos before reaching the Earth.
The Sudbury Neutrino Observatory is a unique neutrino telescope, the size of a ten-storey building, 2 kilometres underground near Sudbury, Ontario planned, constructed and operated by a 100-member team of scientists from Canada, the United States and the United Kingdom.
The SNO detector consists of 1000 tonnes of ultra-pure heavy water enclosed in a 12-metre diameter acrylic-plastic vessel, which in turn is surrounded by ultra-pure ordinary water in a giant 22-meter diameter by 34-meter high cavity.
www.pparc.ac.uk /Nw/Press/sudburysalt.asp?Tx=1   (1151 words)

  
 Colloquium: "First Results from the Sudbury Neutrino Observatory"
The Sudbury Neutrino Observatory (SNO) is a water Cerenkov detector with 1000 tonnes of heavy water (D2O) as its target.
It is designed to measure the solar neutrino flux through the charged-current (CC) reaction, the elastic scattering (ES) reaction, and the neutral current (NC) reaction.
This ability to measure both the CC and the NC interaction rates is unique among all the operating solar neutrino detectors, and would allow the SNO experiment to make a solar model-independent test of the neutrino oscillation hypothesis.
www.physics.berkeley.edu /calendar/data/997397428.shtml   (150 words)

  
 Proton-proton fusion
In the proton-proton fusion process, deuterium is produced by the weak interaction in a quark transformation which converts one of the protons to a neutron.
The neutrinos quickly escape the sun, requiring only about 2 seconds to exit the sun compared to perhaps a million years for a photon to traverse from the center to the surface of the sun.
It is now presumed to be solved with the evidence for neutrino oscillation at the Sudbury Neutrino Observatory and at the Super Kamiokande neutrino detector.
hyperphysics.phy-astr.gsu.edu /hbase/astro/procyc.html   (403 words)

  
 First results from SNO
They combined these first SNO results with measurements by the SuperKamiokande detector in Japan of the scattering of solar neutrinos from electrons in ordinary water (offering a small sensitivity to other neutrino types), to provide the direct evidence that neutrinos oscillate, or change types, as they travel from the Sun.
The Sudbury Neutrino Observatory is a unique neutrino telescope, the size of a ten-story building, 2 kilometers underground in INCO's Creighton Mine near Sudbury, Ontario, which was planned, constructed, and operated by a 100-member team of scientists from Canada, the United States, and the United Kingdom.
The SNO detector consists of 1,000 tons of ultra-pure heavy water enclosed in a 12-meter-diameter acrylic plastic vessel, which in turn is surrounded by ultra-pure ordinary water in a giant 22-meter-diameter by 34-meter-high cavity.
www.bnl.gov /bnlweb/pubaf/pr/2001/bnlpr061801.htm   (1206 words)

  
 Berkeley Lab Currents -- June 29, 2001
SNO can be thought of as a type of telescope, although it has little in common with the instruments most people associate with that word.
SNO is the first neutrino telescope sensitive enough to measure not only ordinary electron neutrinos, but also the much more rare muon and tau neutrinos.
Because of their numbers, neutrinos may hold the answer to some of the most vexing questions in cosmology, and the physics results from the Sudbury Neutrino Observatory may hold the key to unraveling some of these mysteries.
enews.lbl.gov /Publications/Currents/Archive/June-29-2001.html   (7277 words)

  
 [28.02] The Sudbury Neutrino Observatory   (Site not responding. Last check: 2007-10-08)
The Sudbury Neutrino Observatory (SNO) is a 1,000 tonne heavy water Cerenkov detector situated 2,000 meters underground in INCO's Creighton mine near Sudbury, Ontario, Canada.
Through the use of heavy water SNO will be able to detect a number of neutrino reactions, including one sensitive specifically to solar electron neutrinos and another to all active neutrino types.
SNO Collaboration: Queen's University, University of British Columbia, CRPP at Carleton University, University of Guelph, Laurentian University, Brookhaven National Laboratory, Lawrence Berkeley National Laboratory, Los Alamos National Laboratory, University of Pennsylvania, University of Washington, Oxford University.
www.aas.org /publications/baas/v31n5/aas195/142.htm   (270 words)

  
 BBC News | SCI/TECH | Ghostly particle mystery 'solved'
New observations made by a giant underground neutrino detector in Canada show that the solution lies not with the Sun, but with the neutrinos, which change as they travel from the core of the Sun to the Earth.
It was to solve this puzzle that the SNO experiment was conceived nearly 15 years ago.
This means that neutrinos cannot contribute enough mass to the Universe to halt its expansion.
news.bbc.co.uk /hi/english/sci/tech/newsid_1394000/1394811.stm   (611 words)

  
 SNO Group at LBNL   (Site not responding. Last check: 2007-10-08)
The report of a measurement of solar neutrinos through their neutral current interactions with deuterium in the Sudbury Neutrino Observatory represents the realization of an idea of the late Professor Herb Chen for an experiment which would directly resolve the solar neutrino problem.
B decay have been detected at the Sudbury Neutrino Observatory via the charged-current (CC) reaction on deuterium and the elastic scattering (ES) of electrons.
The Sudbury Neutrino Observatory is a second generation water Cherenkov detector designed to determne whether the currently observed solar neutrino deficit is a result of neutrino oscillations.
neutrino.lbl.gov /~snoman   (445 words)

  
 Open Course : Astronomy : Introduction : Lecture 12 : Sudbury Neutrino Observatory Photo
The Sudbury Neutrino Observatory in Ontario, Canada is a 12-m sphere buried 2.1 Km below the ground in an old mine shaft.
It is filled with heavy water, which consists of oxygen and deuterium, an isotope of hydrogen with one neutron, and is surrounded by 9600 photomultiplier tubes to detect light produced as a result of collisions by neutrinos.
This image is used with permission of the Sudbury Neutrino Observatory.
www.opencourse.info /astronomy/introduction/12.sun_interior/sudbury.html   (136 words)

  
 APOD: June 23, 1999 - The Sudbury Neutrino Detector   (Site not responding. Last check: 2007-10-08)
neutrinos, are extremely abundant in the universe but usually go right through just about everything.
Sudbury Neutrino Observatory (SNO) is sensitive to all types of neutrinos, future results
important neutrinos are to the composition of the
antwrp.gsfc.nasa.gov /apod/ap990623.html   (123 words)

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