Team records neutrinos from the Earth's mantle

August 10, 2015 by Bob Yirka report
Team records neutrinos from the Earth’s mantle
Prompt light yield spectrum, in units of photoelectrons (p.e.), of anti-neutrino candidates and best-fit. The best-fit shows the total contribution of geoneutrino, reactor neutrino and background (yellow colored area) and reactor neutrino (orange colored area) assuming the chondritic ratio. The result of a separate fit with U (blue colored area) and Th (light-blue colored area) set as free and independent parameters is also shown. Credit: arXiv:1506.04610 [hep-ex]

(Phys.org)—A team of researchers working on the Borexino Collaboration at Gran Sasso National Laboratory in Italy is reporting that they have detected neutrinos emanating from the Earth's mantle. In their paper published in the journal Physical Review D, the team describes the neutrinos that have been detected at their site and how they came to believe that approximately half of them come from inside the Earth, rather than from the crust.

Neutrinos are neutrally that have nearly no mass, making it possible for them to pass though most matter, such as our bodies. Scientists believe they come into existence as part of radioactive decay and have been working on ways to prove their existence physically by capturing them with detectors. At the facility in Italy, researchers have set up a large underground tank filled with 300 metric tons of liquid scintillator—when a neutrino collides with one of its particles, a flash of light is emitted, indicating that a single neutrino has been detected.

The team at the site has been monitoring the detector since 2007. In this latest research effort, the team is reporting on what have been named geo-, which are neutrinos that come from the Earth, either the crust (many of which are thought to come from man-made nuclear reactors) or the . These particles, the team notes, are actually antimatter versions of neutrinos, and have been recorded before, but the detections were very faint, making it difficult to confirm their source. In this new effort, the team looked at detections occurring over 2056 days, with 5.9 sigma significance.

The large amount of data allowed the researchers to measure the ratios between neutrinos that emanated from the crust versus the mantle because for the first time, they were actually able to distinguish between the two. They also believe that most if not all the neutrinos originated in either uranium-238 or thorium-232 and estimate that 53 of the 77 detected geo-neutrinos emanating from the , were from man-made sources.

The work done by the team is likely to help scientists gain a better understanding of how of material inside the Earth drives other processes, including convection over long periods of time, of rock in the mantle.

Explore further: Two teams estimate the flavor of neutrinos detected by The IceCube Neutrino Observatory

More information: Spectroscopy of geoneutrinos from 2056 days of Borexino data, Phys. Rev. D 92, 031101(R) – Published 7 August 2015. On Arxiv: arxiv.org/abs/1506.04610

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9 comments

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shavera
4.6 / 5 (9) Aug 10, 2015
If you don't understand how to read the plot given with the article:

Dark yellow is what we'd expect to see from our nuclear reactors. The black crosses represent our data. At the low end of the energy spectrum, you see that the data goes up above our reactor neutrino spectrum. So, let's assume that Uranium and Thorium are decaying in the Earth's mantle, and they have spectra light and dark blue. We can scale them up or down, and so we do that until the reactor neutrinos + Uranium and Thorium neutrinos match our data (black crosses) best. This curve is given by the yellow section.

Remember too, the data point isn't at the cross-point of the cross, but really should be thought of as a broad "ellipse" given minor and major axes by the error bars. Somewhere in that ellipse is the data. (it may not be an actual ellipse, but maybe a box or other shape, depending on how independent the measures of error are on one another)
richard_f_cronin
1 / 5 (2) Aug 11, 2015
Neutrinos emanating from the Lower Mantle. Further evidence in support of the GeoReactor proposed by Dr. J. Marvin Herndon. A naturally-occuring fission reactor at the core of every planet, large moon, and ignition source for stars ( big H bombs) caused by the accretion of the heavy Transuranics (U-235) to the core. Similar to the natural fission reactors observed at Oklo Gabon in 1972. Variations in the GeoReactor have caused all heating / cooling cycles since the great Ice Ages and warm Interglacials, as well as supply the lighter elements and simple molecules of life. The extra heat and miniscule uptick in CO2 comes from within. http://www.prnews...091.html
shavera
4.4 / 5 (7) Aug 11, 2015
It is NOT simply enough to point and say "look, this qualitative thing kinda sorta matches this fringe theory I believe in."

What *specific* rate of neutrino production does your pet theory predict? What's the energy spectrum?

Conventional science does assume that there are radioisotopes decaying within the Earth. This seems to be a signal of that effect. Conventional science does *not* assume that this is a "fission reactor" as in a moderated chain reaction, that you seem to be suggesting. What specific evidence would exist (quantitative, not qualitative evidence, at that) that would support the theory?
docile
Aug 11, 2015
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docile
Aug 11, 2015
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docile
Aug 11, 2015
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Osiris1
not rated yet Aug 11, 2015
So Shavera, then I take it the cross point is the centroid of a probability for the assumed 'solution' of the Schroedinger wave function. In any case, the plot taken as a whole appears similar to the positive half of a " 'bell curve' like" exponential function in natural logs.

The site took away the commenter rating for the articles, and trolls have taken away realistic peer review ratings as well. So we readers have lost twice.
abecedarian
not rated yet Aug 11, 2015
" you cannot never disprove "
Care to translate this string of "negatives" to what you really mean?

"... can disprove..."
"... can never prove..."
"... cannot prove..."
....
mytwocts
5 / 5 (1) Aug 16, 2015
"Unfortunately to attitude of contemporary science is not based on original scientific method,"
Much more so than the attitude of cranks though.

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