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Science

Giant Neutrino Detector, 2km Underground 146

Posted by timothy from the where-I-want-to-be-when-the-bomb-drops dept.
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."
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Giant Neutrino Detector, 2km Underground More

Giant Neutrino Detector, 2km Underground

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  • I can pass through matter, such as: smoke
  • And proving that they have mass would help us account for a lot of the 'missing' or 'dark' matter that we think should exist.

    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....
  • It seems the smaller the thing we are looking at, the bigger the machine has to be.
  • I just saw the topic on /. and couldn't help but leaving a quick comment (I'm in the middle of procuring a physics lab write up so don't have much time... :) ) I haven't read past comments so I'm not sure if anyone else has had the chance to brag about actually having been inside the SNO... WELL I HAVE, really I don't know of anywords to describe it adequately... #1 It is HUGE!!!! And the amount of heavy water, millions of dollars of it... #2 It is deep.. you all know that but the whole experience of acutally being in an active mine is a whole other story... some other time :) #3 Everything is sooo absolutely CLEAN!!! Clean is the key word .. They have you go through a multistage cleaning process from taking off your dirty mining coveralls all the way to taking a shower and puttin on the clothes supplied by SNO... Got I could rample on for EVER it was an amazing expirience... Just to let you know, It was a "Physics Society" trip. I'm currently in the Engineering Physics Bachelor program here in Carleton University (Ottawa, CANADA) and the SNO ppl where nice enough to give us a detailed tour of the whole place... For those that might want to know more of my experiance you can reach me at msowka@hotmail.com
  • The Above text about Cherenkow radiation is a troll made up on the spot. Cherenkov radiation is the light produced by a charged particle that is moving faster than the local speed of light in a refractive medium. e.g. in glass light moves at about 70% of c. If a electron moves faster by .7c in glass it will lose energy and emit cherenkov radiation. Its like the optical equivalent of a sonic boom. Cherenkov raditation is the erie blue glow you see when strongly radioactive material is placed in water. Chrenkov radiation is not at all dangerous the ammount of light for all known source is tiny compared with sunlight.

    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.

  • Just to nitpick a little more, but actually Ottawa (The capital of Canada) and Toronto (the capital of Ontario) are both closer to Sudbury than Kingston is. The reason Kingston was mentioned is because a lot of the research is being done at Queens University in Kingston, even though the Observatory is in Sudbury.

    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
  • Actually, it would be more appropriate to label that Motif, by the look of the widgets. It may or may not be *nix.

    --
  • Atomic Energy of Canada Ltd.? (AECL)
  • Really? Why would that be?
  • Sometimes I wonder just what the heck all of those dorfs in Ottawa are doing all day.

    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
  • Congratulations. You have now successfully learned the concept of a continent. Please advance to grade two.
  • Downtown St. Genis Ha! It's a one stoplight town! Downtown consists of that little grocery store, the pub, and a restaurant or two. ;)

    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

  • "A weak CDN Dollar is the reason why we have a tremendous export surplus with the US." Uh... Or, v.v... =)

    "tremendous" -- no. (viz. Japan)
  • I suggest we get scientists on the job, sniffing for other important particles:

    * 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)
  • While high energy collisions provide you with a wealth of information, it's not always the information you need.

    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].

  • Nuclear weapons testing, you mean? A d-u reactor isn't particularly a weapon. =) I know of no general radioactive materials usage ban...
  • What do you think our CANDU reactors run on? Unlike many other reactors around the world, the Canadian CANDU reactors use unrefined uranium and heavy water.
  • In addition to being very clean (and thus with a lot lower background), SNO's primary difference from SK is the heavy water. This stuff provides a lower energy threshold than SK's electron scattering, is sensitive to neutral current interactions, and provides finer energy resolution. That provides different handles on what's happening, and will wonderfully complement the higher energy/higher statistics measurements from SK.

    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).

  • err... the japanese have been doing this for a while... the link is to their public images:
    http://www-sk.icrr.u-tokyo.ac.jp/doc/sk/photo/norm al.html
  • Yes, 24 hour clock is a small improvement, but what we really need is metric time (100000 "seconds" per day). Or maybe we should go for some nice hexadecimal or binary time (65536 "seconds" per day). It's always nice to be able to divide something in half with ease. That's what I've always liked about binary. Yes, I know that it's nice to have other prime factors in a base, but fractions are better, and irrationals are just as irrational anyway.

    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.

  • Retraction -- (and yes I hit preview first, I just didn't READ it)

    Weight should be mass in the above :-)

    This has been another useless post from....

  • Neutrino Beam Through Downtown St. Genis (Score:5)

    by goingware ( 85213 ) on Monday February 26, 2001 @10:49PM (#399451) Homepage
    I spent a summer working at CERN [www.cern.ch] doing my senior thesis for a B.A. degree in Physics at UC Santa Cruz [ucsc.edu] (I was working with the Spin Muon Collaboration [na47sun05.cern.ch], mostly working on data analysis software - I made the mistake of walking down the hall at the physics department asking each professor I met if they could use an experienced software engineer who needed a thesis topic! Mmmm... FORTRAN.).

    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]

  • darn, I was about to correct you. (But hey, if it has mass its gotta have weight :-)
  • Yeah, it does. In fact it's probably some kind of black-hole time-machine, built by the aliens. The media never tells the truth..
  • It's kinda ironic that you mention Stockwell (aka 'Doris') Day seeing as my 24-hour/american reference came from the same guy that pushed for Day to change his name. Stockwell and the 'Alliance' party of Canada were pushing for allowing a referendum with 350,000 votes (less than 3% of Canada's voting population..) The clip where the Doris Day bit came about is available for your plesure at:

    http://www.22minutes.com/realwrapper.php?target=do ris_day.rm [22minutes.com]

  • Man, there were some pretty wicked "fusion reactions" going on in my Sun (SparcStation 10) a couple of months ago. Every time it booted it had an asynchronous fault, and would just keep rebooting, for hours at a time. I couldn't even apply some recommended patches because logins tended to trigger this async fault as well. We just bought a new Ultra to replace it, but I am hopeful that data from the SNO might help me figure out what the problem is and get the machine back in some limited service. I checked for neutrino emissions in OpenBoot but it was a dead end.
  • Remember this?

    http://slashdot.org/articles/99/09/30/1437217.sh tm l

    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? ; )

  • Why not keep the duration of minutes and seconds, so all the computers, etc currently in the World can retain accuracy without complex algorithms that introduce aliasing errors and quantization problems before the properly clocked machines come out.

    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? ; )

  • I think you should be able to mod AND post whenever. To stop abuses, fix it so you cant mod until you`ve posted a number of posts which havent been modded down too much. And make the meta-mod system able to suggest to CmdrTaco (or whoever) that bad moderators lose their ability to mod (for a while).
  • It's proof that the vacuum tube is alive and well... "9600 PMT detectors". Let's see a silicone detector do that.

    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.
  • pass through matter like smoke What's the big deal? I pass through smoke all the time?

    But does the smoke pass through you?

    B
  • Yeah??
    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!
  • Kingston Ontario (home of Queen's University)is, oh, about a 6 hour drive from the actual location of this facility in Sudbury. *doh*

    Going on means going far
    Going far means returning
  • Oops, read further on down in the posts...
  • 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.
    Of course, this isn't as bad as the MINOS project [umn.edu] which is scheduled to start beaming neutrino's from Fermi National Lab [fnal.gov] in Illinois to the Soudan mine in northern Minnesota (800 meters underground) to test for neutrino oscillation. Anyway this beam passes under the state of Wisconsin [umn.edu] (and almost under Madison). After, having lived in all three of those states, it wouldn't surprise me if some conspiracy nuts think that the whole thing is a plot to irradiate Wisconsin ;) .

    --
  • We intelligent Americans hate the English system as much as the rest of the world. It's just Jimmy-Bob-Joe down the corner who don't want no Urrupean bullshit on his pickup truck.
    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.
  • We've already found bosons.
  • Are you European? If you are, it would explain a few things. In Canada, we call people from the USA "Americans". We call people from Canada "Canadians", and we call people from anywhere in North America "North Americans".

    If, on the other hand, you are American, then it is ONLY a Canadian thing. But I think you call yourselves "American" as well.

  • I was not even aware that smoke could pass through matter!'

    I think they mean that the matter is like smoke to these particles, not that the particles themselves are like smoke.
  • After returning from a hard day of hunting seal and polar bear on the pack ice in -60C weather (who knows what the hell that is in fahrenheit, -150F maybe?) and dodging all those hockey pucks, all I like to do is fire up the old 486 to heat my igloo, cook some blubber and read the news on ./. but then i got mad when i saw that the ignorant american who wrote the article claims that sudbury is "near Kingston". When you are writing an article, it's a good idea to do a little bit of research so that you know what the hell you are talking about. saying that sudbury is near kinston is like saying that LA is only a short drive from New York! sudbury is about 7.5 hours from kingston, has a population of 160k in the region and is one of the world's largest producers of nickel. you americans should take the time to check out what is actually in that grey part of all those maps they show you school. btw, you know how wide the US is? well, that's how wide canada is. and you know how tall the US on a map, well, canada is close to twice as tall as that and goes up almost all the way to the north pole. 80% of population lives nestled up to the border, no more than an 8 hour drive. we also still have LOTS of fresh water left. the exchange is only $1.51 US (not $4.50!) and we actually use a measurement system that makes sense, metric, yeah. oh yeah, and we say r-OU-f, not r-u-ff. and we certainly kick the US' ass in hockey.
  • Why just Americans? I was going to point out the same fact on the location and also the length of time this labratory has been open. It certainly isn't "recently" opened - it is over a year in operation - perhaps two - I forget. Stephen Hawking visited it shortly after it was complete and he was impressed.

    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.
  • ever hear of a standadized ballot?? lol, you americans make me laugh!

  • Call it by its proper name: (Score:3)

    by TheDullBlade ( 28998 ) on Monday February 26, 2001 @10:52PM (#399472)
    the SNO ball!
    ---
  • I was lucky enough to do some nuclear physics reaserch at AECL (Atomic Energy of Canada Ltd.) for 2 4-month work terms while in University. I worked in the TASCC (Tandem Accellerator SuperConducting Cyclotron) facility, which was pure research. We did some (very little) commmercial work, and so the entire facility cost the taxpayers of Canada 11 million CND a year. Keep in mind that
    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)

    by Covariance ( 246666 ) on Monday February 26, 2001 @10:55PM (#399474)
    One of the best sites for information on particle physics (for non-specialists) is The Particle Adventure [particleadventure.org].

    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)

    by Anonymous Coward
    I'm not totally sure why people insist on further neutrino study in such fashion. I'm aware that this facility will be even further beneath the surface in the salt mines but it will not really add much valuable information. For those that don't know, you generally want to do these studies in deep salt mines because salt mines do not contain uranium (which decay often) to interfere. However, due to a nuetrinos small mass and size, they are able to pass virtually through anything with very little chance of collision. In general, a single neutrino could travel a trillion light years through nuclei before it had contact. As you can see, reactions from neutrinos are rare. However, you can see them if you know how to look for them. There are generally two popular ways to do this. A.) Use HUGE water tanks containing germanium detectors that detect sudden bursts(photon emissions that cause voltage pulses on the germanium detector) B.) Use huge chlorine tanks to cause a B+ decay since neutrinos can aid in nuclear reactions through the weak force interaction. However, back to my point, such studies of neutrinos don't really aid much. The data has already been collected for neutrino emissions from the sun, from stars, and from the universe in general. To understand field particles we need to go beyond such experiements and stick to spectrometer studies and high energy collisions. Only through this will we really come to understand what's going on. As of now, we are stuck with a theory of leptons(no quark material) and baryons(quark material) theories with no true link. As many like to believe, quarks may indeed have substructure but the truth will be hard to tell due to the fact that the color force between quarks increase with distance and if you put too much potential energy into that field, it will form two new quarks: a quark and a antiquark. So one can see the dilema. However, it's leptons (electrons, positrons, neutrinos, etc....) that are almost the most mysterious. Trying to sort out the connection between leptons and baryons will be a tough one if possible at all. The next big thing is the unified field theory. We have luckily connected magnetic and electric theories into electromagnetic forces with field particles of photons but we have also linked electromagnetic fields to the weak force for certain circumstances. It will be interesting to see what us physicists come up with in the next century.
  • There is no continent named "America" There is a continent called "North America" and another "South America"

    By your logic, we should be "North Americans" as there is no continent named "America"

  • The may have already been covered, but are both systems tought in US schools now?

  • Well I know saying SUDBURY would mean nothing to the americans here.. but honestly, Sudbury is nowhere near Kingston.. it's like reporting on a story and saying near Las Angelas when you're talking about San Francisco.
  • Just think: Neutrino Cheese (now available from Alto).

    --
  • 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).

    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 dollar is good for the Canadian economy because it is an incentive for American business to trade with Canada. If you get 1.45 for every dollar north of the border then you'll buy that Canadian thing-a-ma-jig instead of one found in you borders. (not gonna discuss NAFTA and how that also helps Canada and Mexico)


    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]

  • I think you are allowed to moderate then add to a discussion, just not the oppisite.

    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.

  • Too bad you haven't picked up much of your colleagues' knowlege. Cerenkov radiation, as several others have stated, is no more than ordinary electromagnetic radiation, a.k.a. light. It is possible, while very unlikely, to produce a few gamma rays along with the other stuff, which is mostly within an order of magnitude of visible wavelengths. However, your smoke detector produces more gamma radiation than this experiment will. As somebody else suspected, a pocket MagLite produces several orders of magnitude more electromagnetic radiation than this detector will.

    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?

  • Look here: http://ngs.web.cern.ch/NGS/ [web.cern.ch]

    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

  • Used to be a nickel (i think) mine. Sudbury is big for mining.
  • Some interesting software [queensu.ca] behind this thing, too.
  • And proving that they have mass would help us account for a lot of the 'missing' or 'dark' matter that we think should exist.

    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!

  • "near Kingston, Ontario"? Sort of like Boston is "near" Baltimore?
  • From the majestic Creighton mine near Sudbury, Ontario, Clearly Canadian Heavy Water is the finest spring water you'll ever taste.

    Whether you're replenishing yourself after a tough jog, detecting neutrinos with Chernkov radiation, or just quenching your thirst, you will not be dissapointed with Clearly Canadian Heavy.

    Just compare the neutron count in Clearly Canadian Heavy with other spring waters, and you'll see what makes us the best. Our water is 10% heavier than other waters.

    (Avaliable at your local retailer for about $300 million (cnd).)
  • The thing you have to understand is that the Canadian social welfare system has about reached the stage where there isn't a lot of room for anything else in the budget. Now of course in this country the usual suspects still have a sizeable defense budget to snipe at. In Canada however, defense spending is less than 1/3 ( per capita ) of US levels and that excuse would last all of the couple of weeks it would take to spend the entire defense allocation. Consequently, in an effort to stave off the inevitable day when the public realises they can no longer be kept in the style to which they have become accustomed, gummint is shutting down things like TASCC unless of course the program in question is located in the province of Quebec.

  • It means that the air surrounding the source of the radiation becomes hypersensitive to all communications mediums, including mental/telepathical transmissions.
  • That's the biggest bong I ever saw!
  • The reason that data from various observatories (SNO, Hubble, KPNO, etc.) is not immediately available to the public is that the scientists who run the experiments on the instruments in these obeservatories need to protect priority. For example, you've just spent 5 years and several thousand dollars getting time on Hubble. If you immediately release the data to the public, there's a possibility that someone could take that data and preempt your research, getting the publication and increased grant opportunities for nothing. It's a matter of protecting your investment in time and money. Granted, public funds go into these observatories, but the measurements taken are taken by researchers for a specific purpose. If that purpose is to further their research, then they do whatever is necessary to protect their priority.
  • even from US to SI units

    Dude, everone knows the stonecutters "keep the metric system down."


    --
  • Pop and coffee are full of normal water. Therefore, the stuff that needs to be exact, still is.
  • See correct Astronomy Picture of the Day [nasa.gov] link. (It changes every day.)
  • That's right. Inco donated the old nickel mine.
  • is funny the way Anonymous Coward has conversations by himself. I guess nobody talks to him.
  • There are more photos at the University of Washington Super-K website [washington.edu].
  • canadians are also americans. Canadians are located in the north america, and that makes you north american. You carry the american name. USA what do you call that people usasians. America is not the name of the country. And whats the difference between canada and usa anyways. At least usa fought for its independence. aah I am not making much sence i am sleepy.
  • this was funny in so many ways...

    1: "Uh.. smoke is not capable of passing through matter. ;)"

    Which had this effect:

    2: (Score:3, Informative)

  • APoD picture link correction (Score:3)

    by mosch ( 204 ) on Tuesday February 27, 2001 @01:39AM (#399503) Homepage
    http://antwrp.gsfc.nasa.gov/apod/ap010225.html [nasa.gov] is the correct link for the APoD picture of the giant neutrino detector. That site's worth checking out further though, lot's of interesting pics and info like sand dunes on mars [nasa.gov], and sonic booms [nasa.gov].

    --
    "Don't trolls get tired?"
  • There are already a couple of these things. A similar tank is in the Western US, also underground. Japan is going about it in a different way.

    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.
  • I heard the first successful detection was somehow done with a huge pool of Iodine, which doesn't make sense to me because Iodine sublimes in standard conditions, anyway it happened when a supernova went off, apparently producing a greatly increased number of neutrinos.

    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...
  • wacker/PERISHABILITY OF TECHNOLOGY

    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_tech nology/p_of_t.asp [firstmatter.com]

    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/neutrino com.htm [angelfire.com]
  • To much bay watch, my mistake...
  • The experement you link to is a smaller scale version of the one in the main article. Basically, several facillities have measure the neutrino mass (actually, the mass difference between two types of neutrinos), but no two experements agree. Also, the experemental methods have had several shortcommings, such as the inability of the detectors to see tau neutrinos, and low efficiency.

    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).

  • Doh! forgot the sensless Wayne's World reference: "Hey! No smoke on the matter."
  • Are you sure about this? Do you have anything to back it up? I am skeptical because while the extra mass changes the boiling point and melting points (very slightly), the electronic properties are essentially identical -- solubilities and such ought to be the same. Since nuclear reactions are pretty rare inside humans, the extra neutron shouldn't make much differense.

    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 [yarchive.net]. Especially the part about a D20 concentration of only 50% in a human would stop cell mitosis (the mechanism that is cellular reproduction).

  • I'd like you americans to know.. (Score:4)

    by crlf ( 131465 ) on Monday February 26, 2001 @10:30PM (#399520)
    That SNO is the Sudbury Neutrino Observatory and that Sudbury Ontario is not even close to Kingston Ontario. The confusion comes about from the fact that much of the research being done at SNO is being done by professors from Queens University, located in Kingston.
  • One way they are going to measure neutrinos other than electron neutrinos is to add salt to the water. I think that makes all the neutrinos interact.

  • Event horizon (Score:3)

    by FrostyWheaton ( 263146 ) <mark.frostNO@SPAMgmail.com> on Monday February 26, 2001 @10:31PM (#399525) Homepage
    Does this thing look like the core from the ship in Event Horizon to anyone else??

    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)

    by Nerftoe ( 74385 ) on Monday February 26, 2001 @10:32PM (#399528)
    ...having virtually no mass and able to 'pass through matter like smoke.

    Uh.. smoke is not capable of passing through matter. ;)
  • Ain't it awful when you forget to check 'Post Anonymously'?
  • Then by your logic, Mexicans are Americans too!

  • Super-Kamiokande (Score:3)

    by dido ( 9125 ) <dido&imperium,ph> on Tuesday February 27, 2001 @12:04AM (#399536)

    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)

    by gattaca ( 27954 ) on Tuesday February 27, 2001 @12:23AM (#399537)
    It's a good idea to start uot looking for giant neutrinos because they're much easier to spot than ordinary ones.
  • Shurely they mean that the neutrinos can pass through matter, such as smoke.

    Of course, he could have just as easily said "'pass through matter like lead, Hemos's head, cheesy puffs, etc."
  • SNO is a little different than SuperK because it's designed to see different types of neutrinos.

    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.
  • The experement you link to is a smaller scale version of the one in the main article.

    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.

  • 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.

  • Cuz half of them think Canada has just adopted the 24-hour clock and the other half voted for Bush..

    Do I really need to give a reason?

  • Heavy water is very slightly different than standard water (very slightly higher boiling point, melting point, etc...). The body's metabolism is carefully designed around the exact physical propertied of normal water (everyone knows we are mostly water). If all the beverages and food you consumed contained ONLY heavy water, and you did this long enough for the water in you body to be replaced by entirely by heavy water, you would be dead.

  • Re:So how did they burrow 2 km below ground level? (Score:4)

    by Dr. Evil ( 3501 ) on Tuesday February 27, 2001 @04:55AM (#399560)

    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.

  • Interesting. Has anyone tried that as a cancer cure? Since its stops dividing cells only, it might be effective as a form of chemotheapy?
  • There are several important differences in heavy water and normal water. The first is density, the second is the weaker "hydrogen" bonding found in deuterium, a third is a steric effect (the bond is shorter), it is also more polar but less polarizible than the hydrogen analogue.

    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.

  • Frankly, I'm interested in how they built such a big bunker 2 km underground. Is this facility used for other experiments, or was it just built for this? How did they assemble it this far underground? How do they do air conditioning, life support, etc. there?

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