China turns on giant neutrino detector that took a decade to build

More than a decade after construction began, China has commenced operation of what it claims is the world's most sensitive neutrino detector. Neutrinos are subatomic particles that have no charge and therefore pass through most matter without leaving any sign of their passing. Physics can't fully explain neutrinos, so …

[Anonymous Coward]

neutrinos ... bonk a hydrogen atom

A Panda? ... Eats, shoots and leaves...

Really a massive engineering effort of the PRC in collaboration with international partners.

The devil in the details of the engineering is truly fiendish.

I wasn't clear on how this worked but seems that the occasional sufficiently energetic electron anti-neutrinos from the two equidistant nuclear reactors interact (bonk) with a proton (hydrogen nucleus) in a molecule of the scintillation liquid to produce a neutron and a positron; the latter rapidly annihilates with an electron producing two photons which the photomultiplier tubes detect.

Demonstrates an enviable commitment to big fundamental science by the PRC (or for the MAGAoid addlepated they are just trying to track our nuclear submarines.)

[Mishak]

Similar to

The Super Kamiokande detector in Japan. Let's hope they've taken on board the lessons from when it suffered a cascade failure of its 11,000 (very expensive) photo-multiplier tubes - there's a good video on YouTube about how it works and what caused the failure.

[Elongated Muskrat]

Re: Similar to

I was going to ask what this detector does that Super Kamiokande doesn't. I'm guessing it's just a matter of scale, and location, however I have to wonder if nuclear power plants really produce a noticeably higher level of neutrinos for study than the background stream from the sun. Perhaps ones produced nearer to the detector won't have had time to oscillate (flip from one of three types of neutrino to another) as much as solar neutrinos, so it will allow them to measure this phenomenon better?

[doesnothingwell]

Re: Similar to

Makes me wonder if many governments think they might be able to track reactors moving around the worlds seas? Lots o money for just basic "research". Probably not enough detections and maybe noise, but it makes me wonder.

[Elongated Muskrat]

Re: Similar to

I have to wonder if the neutrino detections are directional? I can't remember if they carry momentum or not, so whether these just detect single scintillations, which would give no indication of the direction the particle came from.

I did read that they do detect things other than neutrinos, which leave different paths through the detection medium. This might be useful, but in order to get good resolution on a source, I think you'd need to triangulate, so you'd probably want multiple such detectors to get any sort of direction and range on a baryon source. Other detectors to do this are probably available at a much lower cost, however seawater is also a very good moderator, so nuclear submarines might not be so detectable this way anyway.

So I'm left wondering, do neutrino detectors detect the direction of travel of the neutrinos? Can anyone answer this? if they did, and you had multiple of these, then theoretically you could use them to track neutrino sources. I wonder if this is a proof-of-concept for this?

[Erik Beall]

Re: Similar to

The primary difference is this is a reactor baseline project (electron antineutrinos from fission), but also somewhat scale and the scintillator used. I was on the MINOS project 20 years ago as a grad student (firing neutrinos from Fermilab to a mine in northern Minnesota) and some of my colleagues at Argonne were working on the "Daya Bay" project, which was a reactor baseline experiment - Jiangmen was created as a move from Daya Bay since they installed a third reactor nearby that would have screwed up the experiment's baselines (need to be equidistant). With water scintillator, Super-K is sensitive to solar neutrinos.

[Anonymous Coward]

Re: Similar to

Perhaps it is looking for a ROI for A.I.,

[brainwrong]

Re: Similar to

I bet you didn't know that the name Super-Kamiokande is Japanese for Fandabidozi!

[Anonymous Coward]

Neutrinos

Like intelligent thought.

They pass some people by without the slightest interaction. (COUGH Trump COUGH)

[Doctor Syntax]

"Jiangmen Underground Neutrino Experiment (JUNO)"

It looks like they ran out of enthusiasm before they finished their backronym. "Observatory" would have done nicely.

[Reggiester]

It *is* called an Observatory, the 'Experiment' part is a rare Reggie error.