They're capturing the helium, so it isn't released usually. Not sure what they do with the nitrogen, I'd guess that is released as it is much cheaper. But in any case the amounts involved in such a quench are only a danger in the immediate vicinity, not outside. So if you're in the same room as a quenching magnet and the room isn't sufficiently sized or ventilated, there could be danger. But that's about the limit to it.
[1] Because it was used regularly in a few of the research labs. Just get a dewar flask that is not made of glass, and ask nicely.
[2] No refrigerator in the lab, the cafeteria didn't have any, most refrigerators had no ice cubes or a huge ice block where there use to be the ice cubes shelf.
It has a lot of uses, from dermatology to machine shops.
Did you even click on the link dude? The picture showing frost on the outside of a metal tube in a sealed tunnel ~100 m under ground is the total extent of the exterior effects...
The only real danger is if you are in an enclosed space and oxygen is displaced. Nitrogen gas is about the least toxic substance imaginable and helium will literally just go away unless you make absolutely sure to trap it.
Interestingly basically all gasses appear to be bad for you in some way. Perhaps the vacuum of space truly is where we belong? /s
https://en.wikipedia.org/wiki/Nitrogen_narcosis
I can't find the study right now but I think this affect is even measurable at atmospheric pressure in that if you give replace the Nitrogen with other noble gasses you can observe improvements in cognitive function.
You have breathed in millions of liters of nitrogen. It is as safe as any substance could possibly be.
The special part is that this energy is put into one particle, which makes it able to achieve other interactions.
Such particles sound scary, but the only special thing about this is that we, humans, have produced that. Our earth is bombarded constantly by cosmic high-energy particles of much much higher energy [0]. I am talking about extra-galactic particles with energy levels unknown to earth.
[0] https://masterclass.icecube.wisc.edu/en/analyses/cosmic-ray-...
Not that it was put that far below ground for safety reasons, it was mostly to save on the amount of land required and to shield the detectors from pesky background radiation (not the other way around).
AFAIK, these areas are restricted while the LHC is operating, so there would be nobody near it (and I believe trying to enter these areas triggers an interlock which stops the whole system before you can get near it).
IIRC from my short time intersecting with the finer points of collider discussion, they locate them in such areas where generally if such things happen, it's a non-issue; but take great pains to ensure that such events don't happen, as it would require potential excavation and removal of a lot of hardware to replace the irradiated sections to restore a contamination free loop. It's also, if I recall correctly, part of why circular paths were chosen instead of things like ovals or capsules for the path shape among other factors I think like optimization for cheapest construction.
Any loss of beam containment would continue on a tangent ensuring one and only one segment of the collider would potentially have to be replaced; other shapes would end up with magnets that were relatively more catastrophic to have fail due to the excursion geometry having more opportunities to escape along a path near parallel to the track, allowing the irradiation of additional accelerator segments. Which would be a hell of a lot more expensive to remediate.
I sometimes laugh, because in the business world, people like to talk about what is 'reasonably forseeable'. I'm a bit of a stick in the mud at such times because I can generally say that exactly no one in the room is actually interested in ptobing the actual boundaries of the reasonably forseeable, as that would require doing too much math. I'm regularly right in that regard.
For anyone genuinely concerned about LHC, we've detected cosmic rays hitting our atmosphere at orders of magnitude more energy than what LHC is doing. https://en.wikipedia.org/wiki/Oh-My-God_particle
https://www.lesswrong.com/posts/C2uvzYeoMkwMmscMx/hamster-in...
It is intellectually dishonest to just say it is not possible for anything to leak and have adverse effects on people without actively researching the matter.
Effects on the local population? You mean those who work there underground? Their voice may change pitch a little, but its only a temporary effect.
Helium is present in our atmosphere. And presumably on your birthday party when a balloon was popped.
Effects on the wider population?
A couple of delays and reorganizations at the surrounding hotels and restaurants.
Basically: the telephone will ring.
Both gases are inert, so they really don't do anything else. There isn't anything to investigate here.
Safety is an important part of the collaboration, which is evident when you work there.
This is evaluated by people who understand physics, chemistry, and biology, and it is the alternative science people that tend to not want to believe that and keep warning of dangers that don't exist.
It is good to always remain critical, but after a while you've used up all arguments to explain that the radiation in your microwave is not radioactive.
I guess the scary part is that they called it a leak instead of a hole. I am sure if I say there is a leak in my sock that some will start to worry.
This isn't an argument. 70 years ago France was conducting atmospheric nuclear tests that caused people and inhabited land to be exposed radioactive fallout.
This one is giving me a headache.
Are people really so scientifically illiterate that they immediately assume that if anything goes wrong with a complicated machine that it will be harmful to their health?
But the beam never colides with the gas deposits. The helium and nitrogen are used to cool the magnets that are used to bend the beam that travels inside a vacuum tube.
[And even if the beam colides with the gas deposits, I don't expect too much radioactive waste. Each particle in the beam has a lot of energy, but there are very few. This links https://public-archive.web.cern.ch/en/lhc/Facts-en.html says "trillions" ( 10^12 ?) of protons, but a glass of water has like 10^26 protons. A nuclear power plant has much more radioactive material and during normal operation produce much more collisions that can turn container radioactive.]
By the way, I worked at CERN for a few years up to the first months of operations of LHC. Furthermore, I've been living in the region since then; for several years, my home was exactly over the LHC tunnel.
I've never got a nightmare from that!