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Giant Neutrino Detector, 2km Underground
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."
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 at Fermilab, you can walk right through the neutrino beamline, which is kinda fun.
I haven't seen anyone mention the Amanda Experiment, 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
1^2=1; (-1)^2=1; 1^2=(-1)^2; 1=-1; 1=0.
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)
It's 10 PM. Do you know if you're un-American?
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!) or build a Really Big neutrino telescope like AMANDA.
Finally, here's a great place to find a lot of neutrino links: The Ultimate Neutrino Page.
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
-- Could you use my software consulting serv
http://www.22minutes.com/realwrapper.php?target=do ris_day.rm
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.
the SNO ball!
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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.
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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 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, they've pretty much won the best-looking physics experiment ever contest.
even from US to SI units
Dude, everone knows the stonecutters "keep the metric system down."
--
python -c "x='python -c %sx=%s; print x%%(chr(34),repr(x),chr(34))%s'; print x%(chr(34),repr(x),chr(34))"
There are more photos at the University of Washington Super-K website.
http://antwrp.gsfc.nasa.gov/apod/ap010225.html 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, and sonic booms.
--
"Don't trolls get tired?"
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."
~~~~~ BigLig2? You mean there's another one of me?
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. Especially the part about a D20 concentration of only 50% in a human would stop cell mitosis (the mechanism that is cellular reproduction).
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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.
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
Comments should be like skirts. Short enough to keep your attention, but long enough to cover the subject
...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!
I wonder what else they'll be able to find out about neutrinos with this detector. I remember the Super-Kamiokande Detector 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...
Qu'on me donne six lignes écrites de la main du plus honnête homme, j'y trouverai de quoi le faire pendre.
It's a good idea to start uot looking for giant neutrinos because they're much easier to spot than ordinary ones.
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.
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 in Kingston is the "home" of the project in spirit (and administration) only.
It is a cool project, just the same.
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.
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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.
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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