"It depends on which accelerator we're talking about, but let's consider the . ...It's minus 271 degrees. ...This is a picture of one of the 15m long s, one of the [beam] bending magnets in the machine... but it's extremely difficult to get your head in there. So... you wouldn't stick your head in the dipole. You'd stick it in somewhere easier... that wasn't cooled down to minus 271."