How can neutrino be detected? What kind of information that neutrino can provide about universe?

Question

How can we detect neutrino, it has little more than 0 mass with no charge. It can pass through anything, doesn't make scintillation.
And what information we can infer from it if we detect it?
I parted with physics long ago and I have forgotten many things and all my current knowledge is corrupted by hundreds of sci-fi movies and discovery channel docs.
Thank you and a happy new year..

I'll pick best answer also
thanks.

Answer 1

It's not a question of mass, it's a matter of interaction cross section with the material of the detector. Photons have zero rest mass, and are easily detected with high efficiency, but the photon interacts by the electromagnetic force and so the cross sections are high. Neutrinos interact only by the weak force, and so the cross sections are many, many orders of magnitude smaller. The usual example given is that for typical neutrino energies, it requires a whole lightyear-thick piece of lead to give a high probability of stopping a neutrino. (Nevertheless, there are situations in nature where materials are optically thick to neutrinos---the early stages of supernovae, for example. Also, the early Universe was optically thick to neutrinos.)

So to make a neutrino detector, the first requirement is a *lot* of material. Huge amounts of water, or ice. The neutrino interacts with the water, and produces a cascade of muons and electrons, all going in more-or-less the same direction as the neutrino, and moving faster than the speed of light in water. This produces Cerenkov radiation that is detected by photodetectors. The direction and amount of the Cerenkov radiation indicates the direction of the neutrino and its energy. Of course ordinary cosmic rays will also produce such an effect, and they are far more numerous, so the neutrino detector only looks at upward-moving particles, i.e. particles that have travelled all the way through the Earth before interacting with the water or ice, because other cosmic ray particles can't do this. Neutrino telescopes are therefore sensitive to neutrinos coming from the part of the sky opposite to their local zenith. (The neutrino telescope at the South Pole only looks at sources in the northern hemisphere.)

The only neutrinos that have ever definitively been detected from an astronomica source are a couple dozen neutrinos detected from Supernova 1987a in the Large Magellanic Cloud. This was a useful and interesting bit of physics, resulting in many scientific papers per neutrino.

The "Ice Cube" neutrino detector at the South Pole is expected to detect neutrinos from high-energy sources. It is partially constructed at this point, and has been in partial operation for a decade. No astronomical neutrinos have yet been detected, although the current sensitivity is near the threshold where detections are expected from high-energy gamma ray sources such as gamma-ray bursters. If there is no detection soon, this will mean that something about our understanding of physics is incorrect. It's not clear, however, that mere detection of neutrinos from gamma-ray sources will tell us much about the Universe that we don't already know.

Answer 2

If it has energy, then it should react somehow with matter in some way.

Answer 3

Neutrinos can be detected through a variety of methods, but the defacto standard has been observing the conversion of chlorine-37 to argon-37 in massive subterranian tanks filled with chlorine-containing molecules, like carbon tetrachloride (dry cleaning fluid). Through elegant observation, and perfection of chlorine-argon detection systems, we have discovered that neutrinos emitted by the sun "oscillate" through 3 different forms: electron neutrino νe, muon neutrino νμ, & tau neutrino ντ. There are also corresponding anti-neutrinos. I don't have time to go through all of the subatomic particle interactions, but I have listed below a little of the information that we can infer from detecting neutrinos.

First, hold you thumbnail out in front of you and realise that there are about 200 billion neutrinos passing through it PER SECOND! Trillions pass through our body every second, even during the night when the sun is shining on the other side of the Earth!

Since neutrinos are of the lowest possible mass in standard particle physics models, and they travel unimpeded through even the most dense objects imaginable, such as collapsing dying stars that are about to go supernova, dark matter, and the rims of black holes, their study also holds promise in Quantum Mechanics in understanding the effects of gravity on quantum levels. Other particles decay, hold charge, or are comprised of complexities that make such experimentation impossible.

For all the math and calculus on these matters (no pun intended), Google and Wikipedia to your heart's content. I don't feel nor enjoy responses from people who take an elegant question such as your own, then copy and paste some differential equations and multivariable analyses to impress you. I just keep it simple, because I am stupid, and contagious ... oh wait, I just plagiarised Nervana! I am becoming a "they."

Hope this little dabble helps. What excited me most about neutrinos is that they, perhaps over any other particle, give us a glimpse into the realms of space and matter that existed just after the Big Bang. Bang a Gong. Get it on. Here I go again! Stop me!

Answer 4

i believe they are detected by the "tracks" they leave. don't quote me though.What's a Neutrino?
What's a Neutrino? Super-Kamiokande Neutrino Oscillations What's It All Mean?


Old UCI Page

Announcement

Paper
(submitted to
Phys.Rev.Lett)

Clinton on
Neutrinos

FAQ

Links

The neutrino and its friends

Neutrinos are one of the fundamental particles which make up the universe. They are also one of the least understood.

Neutrinos are similar to the more familiar electron, with one crucial difference: neutrinos do not carry electric charge. Because neutrinos are electrically neutral, they are not affected by the electromagnetic forces which act on electrons. Neutrinos are affected only by a "weak" sub-atomic force of much shorter range than electromagnetism, and are therefore able to pass through great distances in matter without being affected by it. If neutrinos have mass, they also interact gravitationally with other massive particles, but gravity is by far the weakest of the four known forces.

Three types of neutrinos are known; there is strong evidence that no additional neutrinos exist, unless their properties are unexpectedly very different from the known types. Each type or "flavor" of neutrino is related to a charged particle (which gives the corresponding neutrino its name). Hence, the "electron neutrino" is associated with the electron, and two other neutrinos are associated with heavier versions of the electron called the muon and the tau (elementary particles are frequently labelled with Greek letters, to confuse the layman). The table below lists the known types of neutrinos (and their electrically charged partners).
Neutrino ne nm nt
Charged Partner electron (e) muon
(m) tau
(t)
A Brief History of the Neutrino
bullet 1931 - A hypothetical particle is predicted by the theorist Wolfgang Pauli. Pauli based his prediction on the fact that energy and momentum did not appear to be conserved in certain radioactive decays. Pauli suggested that this missing energy might be carried off, unseen, by a neutral particle which was escaping detection.
bullet 1934 - Enrico Fermi develops a comprehensive theory of radioactive decays, including Pauli's hypothetical particle, which Fermi coins the neutrino (Italian: "little neutral one"). With inclusion of the neutrino, Fermi's theory accurately explains many experimentally observed results.
bullet 1959 - Discovery of a particle fitting the expected characteristics of the neutrino is announced by Clyde Cowan and Fred Reines (a founding member of Super-Kamiokande; UCI professor emeritus and recipient of the 1995 Nobel Prize in physics for his contribution to the discovery). This neutrino is later determined to be the partner of the electron.
bullet 1962 - Experiments at Brookhaven National Laboratory and CERN, the European Laboratory for Nuclear Physics make a surprising discovery: neutrinos produced in association with muons do not behave the same as those produced in association with electrons. They have, in fact, discovered a second type of neutrino (the muon neutrino).
bullet 1968 - The first experiment to detect (electron) neutrinos produced by the Sun's burning (using a liquid Chlorine target deep underground) reports that less than half the expected neutrinos are observed. This is the origin of the long-standing "solar neutrino problem." The possibility that the missing electron neutrinos may have transformed into another type (undetectable to this experiment) is soon suggested, but unreliability of the solar model on which the expected neutrino rates are based is initially considered a more likely explanation.
bullet 1978 - The tau particle is discovered at SLAC, the Stanford Linear Accelerator Center. It is soon recognized to be a heavier version of the electron and muon, and its decay exhibits the same apparent imbalance of energy and momentum that led Pauli to predict the existence of the neutrino in 1931. The existence of a third neutrino associated with the tau is hence inferred, although this neutrino has yet to be directly observed.
bullet 1985 - The IMB experiment, a large water detector searching for proton decay but which also detects neutrinos, notices that fewer muon-neutrino interactions than expected are observed. The anomaly is at first believed to be an artifact of detector inefficiencies.
bullet 1985 - A Russian team reports measurement, for the first time, of a non-zero neutrino mass. The mass is extremely small (10,000 times less than the mass of the electron), but subsequent attempts to independently reproduce the measurement do not succeed.
bullet 1987 - Kamiokande, another large water detector looking for proton decay, and IMB detect a simultaneous burst of neutrinos from Supernova 1987A.
bullet 1988 - Kamiokande, another water detector looking for proton decay but better able to distinguish muon neutrino interactions from those of electron neutrino, reports that they observe only about 60% of the expected number of muon-neutrino interactions.
bullet 1989 - The Frejus and NUSEX experiments, much smaller than either Kamiokande or IMB, and using iron rather than water as the neutrino target, report no deficit of muon-neutrino interactions.
bullet 1989 - Experiments at CERN's Large Electron-Positron (LEP) accelerator determine that no additional neutrinos beyond the three already known can exist.
bullet 1989 - Kamiokande becomes the second experiment to detect neutrinos from the Sun, and confirms the long-standing anomaly by finding only about 1/3 the expected rate.
bullet 1990 - After an upgrade which improves the ability to identify muon-neutrino interactions, IMB confirms the deficit of muon neutrino interactions reported by Kamiokande.
bullet 1994 - Kamiokande finds a deficit of high-energy muon-neutrino interactions. Muon-neutrinos travelling the greatest distances from the point of production to the detector exhibit the greatest depletion.
bullet 1994 - The Kamiokande and IMB groups collaborate to test the ability of water detectors to distinguish muon- and electron-neutrino interactions, using a test beam at the KEK accelerator laboratory. The results confirm the validity of earlier measurements. The two groups will go on to form the nucleus of the Super-Kamiokande project.
bullet 1996 - The Super-Kamiokande detector begins operation.
bullet 1997 - The Soudan-II experiment becomes the first iron detector to observe the disappearance of muon neutrinos. The rate of disappearance agrees with that observed by Kamiokande and IMB.
bullet 1997 - Super-Kamiokande reports a deficit of cosmic-ray muon neutrinos and solar electron neutrinos, at rates agreeing with measurements by earlier experiments.
bullet 1998 - The Super-Kamiokande collaboration announces evidence of non-zero neutrino mass at the Neutrino '98 conference.

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Dave Casper

Answer 5

While a neutrino can travel through miles and miles of lead and never hit an atom, probability works in our favor. Eventually, out of billions and billions of neutrinos coming thru the earth, one will hit something. So we set up detectors around a huge tank of heavy water and wait.

Answer 6

According to the webpage below, neutrinos can be detected by their collision in heavy water surrounded with light detectors.

Answer 7

They are undetectable by all most any device, Science has spent huge sums constructing great tanks of heavy water deep underground, sensors are supposed to pick energy released if a neutrino hits the nucleus of an atom in the water. Just detecting one is all they are attempting to do.