Underwater telescope to study neutrinos

Darksky wrote to us with information about the proposed 'Antares' telescope. The proposal would be to put a telescope 2.4 kilometers underwater, in an attempt to study neutroino/cosmic rays. The telescope would use the the Earth as shield from cosmic rays, and hopefully study the muons liberated by the neutrinos.

Comments

Re:Hmmmm.....

[Faramir]

We can produce massive amounts of neutrinos. But it also takes massive amounts of work. I work on a project called MINOS--Main Injector Neutrino Oscillation Search. We will be shooting a beam of neutrinos (mainly muon type) from Fermilab outside of Chicago to northern Minnesota. At each end, we will look at the flux of each type of neutrino and compare the ratio of types. If the ratio is significantly different than 1, but the overall number of neutrino ratio between detectors is around 1, then this will indicate that neutrinos do indeed have mass. Cool project, but a little beside the point.

Anyway, I've been touring the facilities the last few days, and I can tell you that the accelerator beamline is over 1 mile long, just to reach northern Minnesota. The two detectors, one on each side, will require abou 2,700 tons of steel each (no exaggeration!). So while a neutrino antenna may be able to use different (lower) energies than we are using, I can't imagine that the required equipment would be much different than this. More information can be found at U of Minnesota.

Spelling pickiness

[Pascal Q. Porcupine]

Don't be picky about spelling, lest I respond like this: (alterations in boldface)

• Hey
• , we {really|actually|probably|...} should be looking for gravitons. They would have useful and practical value in society. Imagine {such things as|having|having such things as} graviton space engines, graviton suspensor fields, and the like... yum! But anyway...

  Hemos, it's "neutrino." Man, you need a spelling checker.... ;)

Sorry to be picky, but using .... where ... should be, and vice-versa, and having missing commas, and using "its" instead of "it's," and incorrectly quoting your punctuation, and having atrocious sentence syntax, and then having the gall to point out one insignifigant typo is just a bit asinine.
---
"'Is not a quine' is not a quine" is a quine.

Gravitons do exist.

[Aleatoric]

Gravitons do exist, even if only as a theoretical construct in the realm of quantum gravity, which is the attempt to unify the theory of relativity with quantum mechanics, by trying to explain the behaviour of the universe at planck lenghts (1 x 10 to the -35th power).

A mechanism called perturbative quantum field theory has been successfully used to express and explain electrodynamics. Perturbative quantum field theory is essentially the sum of many method, summing all (or as many as possible) potential pathways which are renormalized after the subtraction of infinities from the corresponding Feynman diagrams. In the realm of quantum gravity, this same approach is being used by some physicists, and one of the theoretical constructs used to aid in this expression are gravitons, described as zero order approximations to quantized gravitational waves in flat space-time. There are already a set of expected characteristics of these particles, such that they are spin two massless particles.

It might not be immediately obvious what, if any, connection a neutrino observatory could have in regard to gravitons, but I would argue that the attempt to understand both the sources and behaviours of neutrinos, especially at high energies, would translate to a potential ability to examine events at the planck length, which to do so in an accelerator would require an accelerator 10 to the 15th times more powerful than any currently existing.

A use for neutrinos

[remande]

Joe Haldeman came up with this one, in a book called The Forever War. Basically, if you can produce and detect neutrinos, then you can use neutrinos as we currently use radio-spectrum photons. Specifically, you have something like a radio where everything is line of sight.

So much for the comm satellite market...

Some further info on ANTARES

[Aleatoric]

Here are a couple of links to the antares site, with some more in depth information about the project.

http://antares.in2p3.fr/antares/antares.html
http://antares.in2p3.fr/antares/booklet/english/ intro_texte.html

Here's a site with links to most of the other research involving neutrinos.

http://www.phys.washington.edu/~superk/links.htm l

SNO

[Tekmage]

The Sudbury Neutrino Observatory is a similar project - a sphere of heavy-water buried 2km underground.

Nonsense.

[Anonymous Coward]

. . . and hopefully study the morons liberated by the nutrinos.

You can't liberate morons, by nutrition or any other means. They have to liberate themselves.

Re:who woulda thunk...

[mph]

The first solar neutrino detector was at the Homestake gold mine in Lead, South Dakota. It used perchloroethylene, a cleaning fluid, to provide chlorine which would be converted to argon in a reaction with neutrinos. You have to count the argon atoms periodically, so you don't get immediate notification of an event, nor good time resolution.

Mont Blanc uses a liquid scintillator, which emits a flash when a neutrino event occurs. This approach has the advantage of providing immediate notification and good time resolution.

The detector with the coolest name is Super Kamiokande, in Japan. It was originally designed to detect proton decay by observing the Cerenkov radiation from the fast electrons that would be a decay product, but it also can detect neutrinos. It also provides immediate notification and good time resolution.

The most famous result from neutrino detectors is that the observations of the solar neutrino emission do not agree well with theoretical predictions.

In addition to the detection of solar neutrinos, neutrino detectors also scored big-time by detecting the neutrino burst of supernova 1987a. Because neutrinos pass through just about anything, these observations were useful probes of what was happening at the center of the SN.

Notes for a talk I gave in an undergrad class are available at http://wopr.caltech.edu/~mph/papers /neutrino.ps. References to other works are included.

wait a sec.

[Wah]

if it turns out the neutrinos actually have mass.


hmm, if E=mc2, and they are moving (thus energy in some form or another, to lose to the muons) wouldn't they have to posess mass? If not, could somebody explain why?

Re:Hmmmm.....

[bperkins]

The amount of energy that you would need to produce enough neutrinos to detect your signal with normal matter makes this impossible.

You'd probably be better off firing x-rays through the earth and trying to detect them that way.

It's been "thunk" before: DUMAND.

[Tau Zero]

A previous idea to do just this, the DUMAND (Deep Underwater Muon And Neutrino Detector) was originally proposed to be put in some very clear water which lies off the coast of Hawaii (IIRC). The detectors would have consisted of long strings of glass buoys anchored to the ocean floor, with very sensitive photodetectors to catch the faint flashes of Cerenkov radiation from newly-created muons racing through the water.

I don't know what became of DUMAND; it may have fallen prey to Congress in a budget cycle, because it was too small to have a constituency to defend it. Kind of like NASA's science programs. <sigh>

Hmm...

[Enoch Root]

That's quite clever, for a number of reasons:

The reason why water is used in radiation shielding is that it contains two Hydrogen atoms per water molecule. Since an atom of Hydrogen has more or less the same mass than a neutron, it acts like a billiard ball: the neutron tends to stop, and the proton is transferred all the kinetic energy. And since the proton is a charged particle, it stops quickly.

Anyway; that means it's good shielding against neutrons. You still have neutrons coming from the environment ("thermal neutrons"), and if the telescope is exposed directly to water, this solves the problem. But you don't need to put it so far down underwater.

Finally, gamma radiation: that's photons. how do you stop these? With difficulty, most of the times. Lead does it, but then lead also emits thermal neutrons! So you have to choose a way to stop both, which you can't.

Except that at this depth, most of the gamma radiation coming from the Sun is absorbed already.

It's a bit of an anti-Hubble: Hubble needs to be in space to be exposed to as much "noise" as possible, whereas this telescope needs to be shielded from almost everything.

"There is no surer way to ruin a good discussion than to contaminate it with the facts."

A non-use for neutrinos

[Tau Zero]

If only it worked that way. The figure I've seen is that a neutrino can go through a trillion miles of lead without interacting with anything, so your chances of detecting an individual neutrino are vanishingly small. Unless you can generate enormous quantities (with enormous energy requirements), you won't get enough of a signal at your detector to be able to communicate. Fortunately for Comsat, their technology is unlikely to be supplanted by neutrino systems any time soon.