Giant Neutrino Detector, 2km Underground 146
yulek writes: "Yesterday's APOD ran an incredible photograph from the recently completed SNO Detector, a giant geodesic neutrino detector buried 2km (!) underground near Kingston Ontario. Neutrinos are some of the most bizarre subatomic particles, having virtually no mass and able to 'pass through matter like smoke.' The SNO Detecter is definitely one of the coolest and most ambitious experiments i've seen in recent years."
Re:smoke pass through matter? (Score:1)
Re:Finding those little suckers (Score:1)
Back in 1998 there was an announcement that some scientists in Japan had determined that neutrinos do indeed have weight. [cnn.com]
Has anyone seen anything more recent on this topic?
This has been another useless post from....
Big Iron (Score:1)
I DON'T WANT TO BRAG OR ANYTHING, BUT... (Score:1)
Re:Not neccessarily. (Score:1)
It of course cannot pentatrate the ground anymore than sunlight light can. In ammount of chrenkov raditation expected from the SNO experiement is of the order of a few tens of photons a day.
Re:Off Topic (few people know where Sudbury is) (Score:1)
Personally I wouldn't expect anyone outside of Canada to be able to point out Kingston or Sudbury on a map. Unless the map is labelled of course...
- Cees
Re:computer-generated images (Score:1)
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Re:heavy water (Score:1)
Re:heavy water (Score:1)
Re:canadian "research" (Score:1)
They usually get good and drunk by 10:30, go to brunch, then get ripped for lunch. Then they go into the House for drunken debating with reporter scrummin' after. Then it's home for whiskey.
And you get to give yourself a raise every term!
______
jeff13
Re:because we're retarded (Score:1)
Re:Neutrino Beam Through Downtown St. Genis (Score:2)
Well after living in St. Genis for a summer, I came back to Madison, WI, where the neutrino beam from the MINOS experiment is passing right below us! The beam goes from Fermilab (Batavia, IL) to somewhere in minnesota, and goes right under us in Madison! If anyone has the opportunity to take a tour of the NuTeV experiment [fnal.gov] at Fermilab, you can walk right through the neutrino beamline, which is kinda fun.
I haven't seen anyone mention the Amanda Experiment [berkeley.edu], which is just plain cool because it's in Antarctica. They're putting their detector in the antarctic ice, again at a depth of about 2km (they use hot water drills).
--Bob
Re:A weak Canadian Dollar is GOOD for Canada! (Score:1)
"tremendous" -- no. (viz. Japan)
Other particles to detect (Score:2)
* unobtainos
* ridiculons
* ephemerons
* bozons
* ludicrons
* phantos
* ethereons
* cowboyneal
I can't wait another day to find out if I am eating empty calories or carcinogens with every meal.
(removed tongue from cheek...hey I have karma to burn)
Re:full reasoning (Score:2)
Neutrino experiments have indeed measured a lot of good stuff, say from the sun, reactors and accelerators, and cosmic rays.
However, since neutrinos are so hard to measure, these measurements are not nearly as precise as you would like. Compared to the accelerator measurements, they are orders of magnitude less precise! The better nu measurements we make, the better information on how leptons behave the theorists can use in building their models of how everything is put together.
Also, the only neutrinos from stars that have been measured are from the Sun and a few from Supernova 1987A. We would dearly love to see neutrinos from other astrophysical sources, but being far away really kills the signal when the Sun (which is right next door) only gives you a dozen or so nu interactions per day. We need to wait for another nearby supernova (check out our Supernova Early Warning System SNEWS [bu.edu]!) or build a Really Big neutrino telescope like AMANDA [berkeley.edu].
Finally, here's a great place to find a lot of neutrino links: The Ultimate Neutrino Page [cupp.oulu.fi].
Re:heavy water (Score:1)
Re:heavy water (Score:1)
Re:Super-Kamiokande (Score:1)
SNO has already shown preliminary results last summer, and will likely publish a detailed paper sometime this year! The whole story will indeed have to wait a few years, though, since nailing down the details of the neutral current vs. charged current measurement involves adding a lot of salt to the heavy water (the better to capture loose neutrons resulting from the interactions).
another detector in japan (Score:1)
http://www-sk.icrr.u-tokyo.ac.jp/doc/sk/photo/nor
Re:I'd like you americans to know.. (Score:1)
Annyyyway... that's a bit too much OT. The whole problem with switching anything (even from US to SI units) is the people who don't want to learn.
Re:Finding those little suckers (Score:1)
Weight should be mass in the above
This has been another useless post from....
Neutrino Beam Through Downtown St. Genis (Score:5)
While I was there I noticed that the CERN neutrino beam went right down the main street of the nearby town of St. Genis in France and on into the Jura Mountains. I wonder if the townspeople in St. Genis would feel comfortable knowing they were being irradiated, even if they understood the particles wouldn't interact.
You see, while the detector that's the subject of this story detects neutrinos of cosmic origin, you can also make them artificially, and with controlled energies and other desirable characteristics, by shooting a high energy particle beam into one end of a long pile of dirt.
The particles shower but are then absorbed by the dirt - except for the neutrinos produced by the showers. Enough dirt, and whatever comes out the other end is pretty much pure neutrino beam.
If you put in an intermediate amount of shielding, you get a mix of muons and neutrinos.
The way you detect these artificial particle beams is typically with packs filled with photographic film sealed in a dark chamber. Just beam it for a while and every zillionth particle will leave a little speck on some of the film.
Ever heard of neutrino oscillations? They proposed the theory to explain the lack of expected neutrino flux in one of the earlier underground neutrino detectors. It takes 10,000 years for heat from the center of the Sun to convect to the surface before it can shine directly on the earth, but neutrinos radiate from the core to the earth in 8 minutes because they don't interact.
Only problem is, we weren't getting many neutrinos. The first suspicion was that the Sun had begun to die but the cooling part of the interior hadn't reach the surface yet - that is, we hadn't visibly received the bad news but had found out ahead of time with the neutrino detector.
If neutrinos change identities into types that a given sensor is not sensitive to, though, it would explain this. But for this to be the case, the neutrino would have to have a very small, but non-zero mass. It's been the work of decades to try to measure this mass.
In the particle beam at CERN they would measure the neutrino flux at different points along the beam to see if they got more and less intense as they oscillated between electron, muon and tau neutrinos.
Enjoy!
Mike [goingware.com]
Re:Finding those little suckers (Score:1)
Re:Event horizon (Score:1)
Re:I'd like you americans to know.. (Score:2)
http://www.22minutes.com/realwrapper.php?target=do ris_day.rm [22minutes.com]
Fusion reactions in the Sun (Score:1)
Re:I'd like you americans to know.. (Score:1)
http://slashdot.org/articles/99/09/30/1437217.s
I worked for the Royal Australian Navy, repairing Gyro compass and stabilizers and also RADAR. Most of the equipment was US Navy and most of the rest was Aussie with a few others here and there, French and what not.
So, I had to deal and im-bloody-perial and metric.
64ths of an inch? Huh? For Christs sake! Metric is at least logical to work with in your head. I could'nt be bothered with imperial. A foot? Huh? Mine or yours!?!? A quart(er) of what? A litre. Huh? ; )
Of course, perhaps Americans reading this probably think I have this arse (or is that ass) backwards! Since I learnt only metric at school (with a quick look at imperial in metalwork classes), I am biased and as such, perhaps I do have it all wrong... then again... whats 7/64ths of an inch off 5 yards, 3 inches and 60/64ths of an inch? ; )
Re:I'd like you americans to know.. (Score:1)
How about minutes:seconds?
0000:00 being midnight
0060:00 1am
1181:47 6:38:47 pm
1439:59 23:59:59
For use by humans on watches and computer screens, and just plain old seconds for computers...
Oh, wait a second, you say Unix was built on that concept of time!?!? And what's that? Unix time is only limited by the word size used, so our Sun will go supernova before a 64bit word rolls over?
Wow! Did Microsoft innovate that? ; )
Re:Just plain wow. (Score:1)
It's proof... (Score:1)
For a good reference on PMT's goto http://www.hamamatsu.com [hamamatsu.com]. I'd be willing to bet they made the PMT's.
Re:So? (Score:1)
But does the smoke pass through you?
B
Re:"Near Kingston" (Score:1)
Toronto, Sault Ste Marie, London and I belive Windsor are all closer to Sudbury than Kingston is.
Kingston and Sudbury are located pretty much in opposite ends of Ontario, and that's not att all near!
Its a good thing you aren't tour guides. (Score:1)
Going on means going far
Going far means returning
Re:heavy water (Score:1)
Re:Neutrino Beam Through Downtown St. Genis (Score:2)
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Re:I'd like you americans to know.. (Score:1)
I think that we just need to go cold turkey like the Canucks did. The hicks will deal.
I read an "editor's challenge" in Popular Mechanics once, on this topic. There were two letters published. The one in favour of metrification was from a well-spoken Canadian and he outlined his argument well. The one against metrification was poorly organised and his main arguments were: "well, the French had to come up with an easy system because they killed all of their smart people in the revolution" and "The metre is less accurate than the inch" whatever he was smoking, it was some good shit.
Re:Other particles to detect (Score:1)
Re:because we're retarded (Score:1)
If, on the other hand, you are American, then it is ONLY a Canadian thing. But I think you call yourselves "American" as well.
Re:heavy water (Score:1)
I think they mean that the matter is like smoke to these particles, not that the particles themselves are like smoke.
Re:I'd like you americans to know.. (Score:1)
Re:I'd like you americans to know.. (Score:2)
We'd assume Americans might not know this because anyone reading this site is a certified nerd, and all nerds in Canada have read/heard about this labratory - it was headline news several times in the last year. It is located in an old nickel mine, and a famous one at that - not much nickel in Kingston, but everyone in Canada knows the big nickel in Sudbury.
We also have empirical evidence from a TV show run up here called This Hour has 22 Minutes, in which the same dude that proposed the referendum to change Stockwell Day's name to Doris Day (by law) has visited such places as Harvard Univ., and asked professors and learned students there about obviously false stories occuring in Canada, such as the sad news of the closing of Eaton's University, "the last University in Canada". Of course there are dozens of Universities in Canada, and you might expect a Harvard professor to see through that, or even get a little suspicious when reading the mic label in front of his nose that says "22 minutes". In case you didn't know, Eaton's is actually a department store. Rick Mercer had no problem locating dozens of students at Harvard that fell for this question.
The basic fact is, Americans generally have poor knowledge of North American geography. For some reason, Canadians know more about the U.K. and U.S. than the other does about here. I blame elementary school.
oh yeah! (Score:1)
Call it by its proper name: (Score:3)
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canadian "research" (Score:2)
1) this was a world class research center with researchers from all over the world using those facilities, but
3) practically no one in Canada ever knew or cared or will ever know about TASCC..
Anyway, the government cut funding to this facility, (just TASCC, AECL makes and sells CANDU reactors for $$). Wondering what I would do for my next co-op job, my supervisor hooked me up with an interview with Art McDonald (director of the SNO project), who told me I could work at SNO. The catch was, almost no pay. (So now I write software. (had to pay for school somehow)) My point? Let's hope there is enough funding for this to see it through. Just imagine destroying a world class research center because of a measly (in governemt terms) price-tag. It could happen again.
Information on Neutrinos (Score:5)
Neutrinos are the least studied elementary particles because of they interact very, very rarely. It's no joke that they can "pass through matter like smoke", as the story said. The typical neutrino can pass through several light-years of lead without interacting once. The only reason they can be detected at all is that a tremendous number of them pass through the Earth every second. I forget the exact number, but it's something like trillions per square meter per second. Even so, a decector the size of SNO will only see a few hundred events per second. On the other hand, this is also why neutrino experiments like SNO or Super-K [u-tokyo.ac.jp] are so exciting for astrophysicists. The light that we see from the sun has all come from the surface, photons produced in the core can't make it through the sun to get to the earth. Neutrinos produced in the core can easily penetrate the whole of the sun and reach the earth. As a result, a very good neutrino telescope can look directly into the core of the sun. There are a berzerk number of other reasons to be excited about neutrino experiments, see the Particle Adventure for more.
Oh, and if you thought the SNO picture was cool, check out some of the photos on the Super-K [u-tokyo.ac.jp], they've pretty much won the best-looking physics experiment ever contest.
full reasoning (Score:1)
Re:because we're retarded (Score:1)
By your logic, we should be "North Americans" as there is no continent named "America"
Re:I'd like you americans to know.. (Score:1)
Near Kingston? (Score:1)
Re:Its a good thing you aren't tour guides. (Score:1)
Re:Neutrino Beam Through Downtown St. Genis (Score:1)
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Re:Super-Kamiokande (Score:1)
Actually, the detection or neutrons from the neutral-current interactions at SNO will use helium-3 tubes, not salt. The two methods were competing, but the 3He tubes leave the D2O pure, which helps keep the background down.
A weak Canadian Dollar is GOOD for Canada! (Score:1)
So your 0.67 is now in circulation in Canada and some Canadian gets to buy groceries. A weak CDN Dollar is the reason why we have a tremendous export surplus with the US.
-
www.jmagar.com [jmagar.com]
Re:Just plain wow. (Score:1)
Anyway - I thank those who have added insight to my original post. I had always wanted to get more facts about the "just like normal H2O" idea.
Re:Not neccessarily. (Score:1)
To point out some other problems with your earlier posts:
Being 2 km undergound is absolutely necessary to get meaningful readings. At or near the surface, evidence of the neutrino reactions would be completely washed out by cosmic radiation. What "uderground atmospheric properties" do you think are going to alter the readings?
And what the hell is "creating a medium of radio frequency hypersensitivity in the surrounding air" supposed to mean?
similar experiment by Cern/INFN (Score:1)
There's a neutrino beam at CERN (north of the Alps) sending neutrinos which get detected in southern Italy 6km deep inside the Gran Sasso mountain.
ms
Re:So how did they burrow 2 km below ground level? (Score:1)
SNO Software (Score:1)
Re:Finding those little suckers (Score:1)
Um, no. In order to make up the "missing mass," neutrinos would have to have a mass of at least 10 eV, which they don't. The upper limit on the mass of the electron neutrino is less than a few eV, as determined by tritium beta-decay experiments.
The masses claimed by neutrino oscillation experiments are much, much smaller, like 1e-5 eV or less. Of course, the oscillation experiments don't observe the mass directly; they can see the difference in masses between two neutrino flavors. In any case, neutrinos cannot make up the missing mass of the Universe.
Neutrinos are incredibly important cosmologically, anyway. The density of neutrinos in our galaxy is about 1e9 per cc. That includes inside you! Unlike many other particles, the probability of a neutrino interacting goes down as the neutrino energy goes down, so these primordial neutrinos are undetectable.
Another cool and interesting factoid: when a supernova explodes, only about 1% of the total energy is emitted as light and kinetic energy. The other 99% is neutrinos. So even though a supernova can be optically brighter than the rest of its galaxy put together, what you see pales in comparison to the neutrino flux!
Depends on what you mean by near.... (Score:1)
Advertisement (Score:1)
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Re:canadian "research" (Score:1)
Re:Not neccessarily. (Score:1)
I Wish I Had That in College... (Score:1)
Re:Not Yesterdays... (Score:1)
Re:I'd like you americans to know.. (Score:2)
Dude, everone knows the stonecutters "keep the metric system down."
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Re:Just plain wow. (Score:1)
Corrected image link (Score:1)
Re:So how did they burrow 2 km below ground level? (Score:1)
Re:heavy water (Score:1)
More photos (Score:2)
Re:because we're retarded (Score:1)
Funny things (Score:1)
1: "Uh.. smoke is not capable of passing through matter. ;)"
Which had this effect:
2: (Score:3, Informative)
APoD picture link correction (Score:3)
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"Don't trolls get tired?"
So what? (Score:1)
As far as whether they have mass or not; giving them a small mass does explain why they detect far less of these guys then if they were purely massless. I think right now the most being detected is like 40% of what they expect; adding mass brings that percentage up significatly. It was a Russian scienentist that came up with that part of the theory.
My 2 cents (Score:1)
Secondly, and this is a bit ridiculous to even mention, well every particle having an anti-particle, I believe the goal of detecting or creating anti-neutrinos would be an even greater achievement. But I'm way out of my field here...
neutrinos: vehicles of communication? (Score:1)
Technology has moved us from the age of planned obsolescence to the era of inherent obsolescence, obsolescence hardly confined to software. Consider Motorola's 1998 launch of the world's first digital, global communications system. The technology supported the Irridium launch was obsolete well before the final rocket thruster fired. Fermi Labs had already fired a neutrino 235 miles into the earth, essentially demonstrating that it was possible to send media messages through the earth.
http://www.firstmatter.com/newsletter/1999/10_tec
University of Hawaii, Manoa/ET NEUTRINO SPEAK?
Calculations showed that the detection of extraterrestrial neutrinos could be achieved with as little as a cubic kilometer of seawater if there is a transmitter within about 3,000 light-years. Any artificial signals should be quite distinctive since the neutrinos would come from a single direction in the sky and have a very well-defined energy. http://www.angelfire.com/on2/daviddarling/neutrin
Re:It's proof... (Score:1)
Re:Finding those little suckers (Score:2)
This experement, if successful should detect a large percentage of the solar neutrinos, and more importantly, all three types. This should allow for a fairly accurate measurement of the mass deltas and the mixing angles, as well as provide internal checks and balances. (if the sum of the mass deltas between the three types is not zero, something is horked).
Re:smoke pass through matter? (Score:2)
Re:Just plain wow. (Score:2)
It isn't that I don't this it is possible, I just am surprised and would like to see some reason other than "the body's metabolism is crafted around regular water" -- what processes are disrupted or altered?
READ THIS (Score:2)
I'd like you americans to know.. (Score:4)
Re:Finding those little suckers (Score:2)
Event horizon (Score:3)
Homer, that's not God, it's just a waffle Bart stuck to the ceiling
I know I shouldn't eat thee
smoke pass through matter? (Score:3)
Uh.. smoke is not capable of passing through matter.
Re:third post (Score:2)
Re:because we're retarded (Score:2)
Super-Kamiokande (Score:3)
I wonder what else they'll be able to find out about neutrinos with this detector. I remember the Super-Kamiokande Detector [u-tokyo.ac.jp] at the University of Tokyo Institute for Cosmic Ray Research. They detected the first neutrino oscillations with it back in 1998 and did an experiment a couple of years ago with an atrificial neutrino beam that further supports the hypothesis that neutrinos oscillate and therefore possess a small amount of mass. I guess this Canadian detector ought to support the theory further.
It will probably be many years before the SNO can produce any kind of useful experimental results, though. Neutrino interactions are of extremely low probability...
Giant neutrinos (Score:3)
Re:smoke pass through matter? (Score:2)
Of course, he could have just as easily said "'pass through matter like lead, Hemos's head, cheesy puffs, etc."
Re:Super-Kamiokande (Score:2)
In SuperKamiokande, the target is simply water. Neutrinos come in, scatter off a nucleon, and produce a charged lepton (electron, muon, or tau) and this charged lepton produces cherenkov radiation. The works well for superk, since its goal is to measure neutrinos with energies above 5 MeV. Below that energy, the charged leptons just aren't energetic enough to travel far enough to produce enough light to be detected.
The purpose of SNO is to push the energy threshold down lower, to around 2 MeV. This can be done by adding a chemical scintillator to the target. Chemical scintillators become excited by the passage of high energy particles and emit light, so a typical low energy reaction in SNO will produced more light than one in SuperK.
Lowering the energy threshold is import if you want to study what goes on in the Sun because the fusion processes taking place produce a very particular neutrino spectrum. Because the fusion of hydrogen into helium doesn't occur in a single step, you can distinguish neutrinos coming from different stages of the reaction by their enery. Most of the neutrinos emitted from the sun are actually around 1 MeV and aren't energetic enough to even be seen by SNO, but SNO does a good job of observing more of the spectrum than previously seen by an experiment on this scale.
The experiment with the artificial neutrino beam that you refer to is K2K [neutrino.kek.jp] and it's still on going. Although K2K's results so far are not inconsistant with neutrino oscillations, it's just too early to tell. K2K will run for another three years to get enough data to make a conclusive statement.
Re:Finding those little suckers (Score:2)
Uh, no, it's not. SNO is a sphere with a 6 meter radius, and SuperKamiokande is a cylinder with a 20 meter radius and 40 meter height. SNO is the small one.
The experiments aren't really comparable, though. The detectors use different targets. SuperK uses ordinary water, and SNO uses heavy water. They're designed to measure different energy ranges. In short, they see different neutrinos.
several facillities have measure the neutrino mass (actually, the mass difference between two types of neutrinos),
Actually, the difference in the squares of the the masses of two types of neutrinos.
no two experements agree
This is not true either. First of all, there are at least three types of neutrinos. If you take three types of neutrinos, and pair them, you can arrange them in three different pairs so you can measure three different mass differences which are all different but that's not a disagreement, you've just measured different things. Second of all, not all experiments disagree!
Also, the experemental methods have had several shortcommings, such as the inability of the detectors to see tau neutrinos, and low efficiency.
Low efficiency is not a shortcomming. There's no shortage of neutrinos flying around, so the fact that you miss most of them is a blessing, not a curse.
And some detectors can see tau neutrinos, such as AMANDA [berkeley.edu].
This experement, if successful should detect a large percentage of the solar neutrinos, and more importantly, all three types.
All solar neutrinos are electron type, so your statement makes little sense. SNO has no ability to distinguish neutrino flavor. It was designed and optimized to measure electron type solar neutrinos, and that's pretty much all it does.
"Near Kingston" (Score:2)
Just for the record, SNO isn't so near Kingston. It's near Sudbury (it is, after all, the Sudbury Neutrino Observatory), which is probably a 6 hour drive from Kingston. Queen's University [queensu.ca] in Kingston is the "home" of the project in spirit (and administration) only.
It is a cool project, just the same.
Re:I'd like you americans to know.. (Score:2)
Do I really need to give a reason?
Re:Just plain wow. (Score:2)
Re:So how did they burrow 2 km below ground level? (Score:4)
It is in Sudbury's Creighton mine. Technically, it is in a suburb of Sudbury. Despite working for the project, I don't recall it's name. Just outside Lively I think... And although Queens is a major participant, Universities all over North America are contributing to one degree of another. IIRC there was quite a bit of U.S. hardware lying around, the University of Pennsylvania provided computer hardware, Oxford did some heavy computer programming during the engineering phase, they may have gone beyond. Laurentian in Sudbury provided labour and communications, that was my 'in'.
It is an active nickel mine. The bulk of the mining was ocurring at the 7200/7400 ft level, it may have gone deeper, or fluctuations in Nickel prices may have moved them to another drift. The observatory is at 6800 ft.
The observatory is a barrel-shaped cavity. They extended a drift into granite. It is 2km underground to achieve passive sheilding from radiation. When I was there they were working on the problem of building a bottle in a cavity.
Re:READ THIS (Score:2)
Re:Just plain wow. (Score:2)
The density effect makes little difference except to the canals in the inner ear - these are finely tuned so a small change in the density of the liquid can cause an effect here. The effect is that you get dizzy and fall down.
The second effect is due to deuterium "hydrogen bonding" being weaker that normal hydrogen bonds - the effect can be seen in chromatography where deuterated analoques elute first due to this effect. The effect, while small, can have a major effect on metabolic pathways in cells etc.
The third (bond size) can have important effects when proteins are involved - the atom may be in the wrong place.
The final two will alter the rates of reactions (albeit very slightly)
All these add up to deuterium and hydrogen being identical chemically in all respects except for rate constants and equilibrium points - the very things that are important for biological processes.
So how did they burrow 2 km below ground level? (Score:2)