This is the CERN press release regarding the status of the Large Hadron Collider. The bottom line: There was a release of helium leak inot sector 3-4 (which I’m pretty sure is next to sector 7g). They thik they know what caused the leak but they are not sure.
In order to investigate, they have to warm up these parts from near absolute zero to room temperature, inspect, repair, fiddle, but with/of what and in what manner is unknown, then cool it all back down again. The warming up and cooling down each take weeks.
If the repair and inspection takes only a few days or a couple of weeks, the entire cycle will bring use to a point in the calendar where there is a required “maintenance shutdown.” This is an annual period during the winter when the LHC is required to not operate (and thus, a good time to do maintenance … so they call it a maintenance shutdown, even though that is not what it is) owing to the cost and/or availability of electricity. So, no matter how long the repairs/inspection takes the machine will be shut down until late winter or so.
Now, keep in mind that even though the press release is worded in such a way as to allow unsuspecting reporters to believe that the engineers have a clue as to what is going on, it is also clear from the press release that they do not know what went wrong. Perhaps a part failed. Perhaps some adjustment needs to be made. Perhaps there is a fundamental design flaw somewhere that will require re-engineering.
On the positive side, the press report also states (but mainly by quoting outside sources) that this is a complex machine and that this kind of machine should be expected to break down frequently, especially in the early phases of its existence.