SuperK Neutrino Detector Severely Damaged.

Eric Sharkey writes "The Super-Kamiokande neutrino detector, which announced the discovery of neutrino oscillation and mass in 1998 (covered by Slashdot at the time), has been severely damaged. The NY Times (free reg, blah blah) has an article here. Most of the phototubes have been destroyed. Repair estimates top $30M, leaving the world far less capable of observing the next supernova neutrino burst, should it arrive before repairs or a replacement could be completed." CD: I called the lead of the project and he was in the tank checking out the damage. The webpage for the Super-Kamiokande is here. There are pictures for you to peruse.

Comments

Supernovae

[the Atomic Rabbit]

...leaving the world far less capable of observing the next supernova neutrino burst, should it arrive before repairs or a replacement could be completed.

While the accident is a tragic blow to some valid and interesting research, no one should lose any sleep over the possibility of being unable to analyze the next big supernova before it can be repaired. After all, supernovae on the scale of SN1987A occur once every few hundred years (the last two occurred in 1054 and 1572.) I suspect repairing Super-K will take significantly faster than that.

Even in the minuscule chance that a big supernova will occur in the meantime, Super-K isn't the only neutrino observatory around. The Sudsbury Neutrino Observatory, a similar experiment, is online and producing some very good results.

Re:Supernovae

[the Atomic Rabbit]

Oh, and in case anyone is misled... the neutrino observatories are assuredly NOT there to catch supernovae. They mostly detect neutrinos coming from the Sun, which are produced during the solar fusion process. The data from Super-K and SNO is shedding light on some problems in solar physics and elementary particle physics.

I doubt any grad student is patient enough to work on an experiment that gets one event every five hundred years.

Re:Supernovae

[astrophysics]

While it's true there are multiple observatories, they aren't merely copies or bigger versions of each other. The different observatories are senstive to neutrions of different energies.

SuperK used ordinary (but pure) water. SNO used pure "heavy water", that is water where the hydrogen has a neutron. SNO has recently added salt to their heavy water, since comparing the reaction rates with and without the salt will provide a very interesting ratio for understanding the mass heirarchy of neutrinos. Other detectors have used other media for detecting neutrinos, such as gallium.

Just speculation, but...

[sting3r]

One of my colleagues used to work at Fermi Lab and he mentioned once that the light sensors that were damaged are extremely sensitive to saline solutions (such as water that has any appreciable amount of non-neutral-pH molecules). His speculation was that the deionized water that they were using had developed impurities in it, possibly from rusting pipes or failed filters, and those impurities set off the chain reaction in question.

Naturally this is all speculation, but it sounded plausible to me. Does anyone with a stronger chemistry background than mine know if this is a likely cause?

-sting3r

Neutrinos

[Thaidog]

...have no charge and no mass... are very fast and pass through the planet so fast most detection has to be done underground... Damn I watch too much public TV...

Re:Neutrinos

[mmontour]

...have no charge and no mass...

No charge - correct. However, as the article mentions, recent experiments indicate that neutrinos have some mass. They also have spin 1/2, like electrons.

are very fast

This is related to mass. If they had zero mass, they would travel at the speed of light (like photons, which have no rest mass). However, if they do have mass, then they have to travel at slightly less than the speed of light.

Supernova observations can be used to estimate neutrino mass, by measuring the time difference between the arrival of visible light from the supernova, and the arrival of a neutrino pulse. Over those vast distances, even a very small difference in speed could lead to a significant difference in arrival times.

and pass through the planet so fast most detection has to be done underground...

This is a bit off. The interesting item is that most neutrinos pass right through the planet without interacting with any atoms. Because they interact so weakly with matter, a detector will only see a very small number of events caused by neutrinos, even though there are bazillions of neutrinos passing through it every second.

However, a detector on the surface of the earth would also see events not from neutrinos, but from other cosmic radiation like muons (actually, muons generated in the upper atmosphere by cosmic radiation). Going deep underground blocks out all particles except neutrinos, enabling the experimenters to get accurate measurements.

Reports of its demise have been....

[wholesomegrits]

Premature at best.

It's a real shame, the loss the Japan lab, but I can't help but think that the lab being built in Western South Dakota will be even more important. I cannot find a decent date on completion, but this page explains a newer, better neutrino detection lab being constructed right now.

The location even better (8,000 feet deep, insulated from nearly every form of interference) and the site has fanstastic support from the state and federal government. The Japan lab isn't the only one in existance -- there are others in Ontario and the South Dakota lab has had facilities in operation since 1967.

The articles, both the Slashdot commentary and the NYTimes article, predict a savage demise. But other labs, especially the South Dakota lab, offer a huge potential to pickup the slack.

Re:Insurance

[CrazySailor]

In the US, the government is considered "self-insured" and is not permitted to purchase policies from commercial providers. Any adequately large business may do this as well. It comes into play when I'm on travel and not permitted to purchase the various damage waivers on rental cars. The travel office refuses to reimburse them.

Incorrect

[DoctorNathaniel]

Neutrino observatories ARE there to catch supernovae, although this is not their primary reason for existance.

SNO is indeed on the case for supernovae explosions, but the fact of the matter is that one observatory simply isn't enough; because of unvavoidable detector downtimes (maintanence, calibration, equipment failures, instrumental problems, etc etc) you can't run 24/7/365 with these guys. Also important is that one really wants both detectors live: you want verification that there really IS a supernova in progress before you swing the Hubble around to look for it.

Add to that the complimentary advantages of the detectors (angular resolution and high statistics in SK, antineutrino detection and energy resolution in SNO) and you really really don't want SK going down if you're a neutrino astrophysicsist interested in supernovae.

--Nathaniel, recent PhD with SNO

Will it come back up? I hope so. But it's hard.

[DoctorNathaniel]

Although news has been sketchy, I am hopeful that they had the phototubes insured. (Any other financial cost will be small compared to the PMTs.) Even if they didn't, I think it's not too unlikely that Japan and the US will re-fund the experiment. SK has done some really amazing work, and is committed to a long-term project with KEK (the K2K long-baseline experiment). I can't imagine that they would simply dump this very productive and valuable resource. But then, who am I to predict the whims of politicians?

However, even if money is no object, timeline could be. These 20-inch PMTs are not exactly off-the-shelf items, and Hamamatsu(the company that provides them for SK and many other experiments around the world) has substantial lead times in getting their production lines up. All told, even under the best of conditions, the process could take 2 years, by which time SK will be in severe competition with a lot of other experiments: Borexino, KamLand, MINOS, etc. etc.

They MIGHT use the time to build super-duper-K.. putting a magnet in the water to look for lepton charge sign from atmospheric neutrinos, but that seems a bit farfetched and difficult.

---Nathaniel, messenger of doom

P.S. I call dibs on the SK linac when it gets scraped!

Ice Cube

[DoctorNathaniel]

Oh, I forgot to mention: IceCube (and AMANDA) are not really in the same buisiness as Super-K. The really big ice experiments are looking for cosmogenic neutrinos, and very-high energy atmospheric neutrinos, not the same energy band as SK. SK in addition does a lot of work on solar neutrinos and other physics besides; the ice cube is not really in competition... although it is extremely cool. Not to say cold.

--- Nathaniel
Who has worked in Sudbury (SNO) and Minnesota (MINOS) and wants no part of AMANDA (south pole)

Cigar insurance

[Anonymous Coward]

Here's what Snopes has to say about this. It is an urban legend.

stuff about neutrinos

[Anonymous Coward]

For me it seems to be that most of the /. readers do not have a clue what neutrino is so here is a link

neutrino

So make some studies before posting.