A rare LHC tour | Hacker News Reader

A rare LHC tour

arstechnica.com

68 pointsstickhandle8 comments

> when the LHC runs, the chambers housing the detectors experience intense radiation

I thought that it was very energetic but low intensity radiation (outside the main tunnel). Does anyone have more data about this? How many "normal radiography" equivalents do you get for standing there for a minute?

Anywhere around the accelerator you are going to have massive cyclotron radiation ( ie. the photons emitted when you coerce of near light speed proton out of a straight line).

In addition, at the detectors themselves, you have all sorts of radiation from the collisions. Muon, gamma, etc.

The author does pass on a good point, the biggest danger is oxygen deprivation from liquid helium, argon, and I assume Nitrogen ( though not mentioned ).

Well no, the biggest risk is falls according to a CERN safety presentation from this year:

https://indico.cern.ch/event/383674/contribution/6/material/... (page 42)

(Handling is pretty vague though, and it was hard enough to track down this paltry statistics, so I'm glad falls won)

But oxygen deprivation is probably the biggest "exotic" hazard.

I took a tour of the ATLAS experiment last year, and the guide said that if the LHC was operating, the radiation where we were standing would be fatal in seconds.

You can actually visit many CERN sites with Google Street View:

CMS: https://www.google.com/maps/views/view/streetview/cern/cern-...

Atlas: https://www.google.com/maps/views/view/streetview/cern/cern-...

Alice: https://www.google.com/maps/views/view/streetview/cern/cern-...

LHC: https://www.google.com/maps/views/view/streetview/cern/cern-...

LHCb: https://www.google.com/maps/views/view/streetview/cern/cern-...

On the last image on the last page there's image of some copper devices with a description:

> These strange copper devices help take electric energy and convert it into kinetic energy of particles.

Pardon my ignorance, but isn't that just a fancy way of saying that it is a motor or some kind of pump?

Those are radio frequency cavities which accelerate the protons. A standing electromagnetic wave is formed which oscillates at just the right frequency so that the bunches are always accelerated as they pass from one section to the next.

Those are resonant cavities, the RF pushes the particles.

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