Universe Today
[/caption]On September 19th,
CERN announced
that the Large Hadron Collider had suffered a major incident, known as a "quench". An electrical short between two of the superconducting magnets had kick-started a helium coolant leak inside the tunnels housing the accelerator ring. The quench caused the magnets to rapidly heat up, severely damaging them. The violent release of coolant ripped equipment from their concrete anchors, ensuring a huge repair operation would need to be carried out. However, it was a while before engineers were able to access the damage and the news wasn't good: The LHC would be
out of commission until the spring of 2009
at the earliest
. That was such a sad day.
[caption id="attachment_21901" align="alignleft" width="250" caption="The first replacement magnet for sector 3-4 arrived at CERN last Saturday (CERN)"]
[/caption]Late last month, CERN Director-General Robert Aymar gave a presentation to the 84th Plenary Meeting of the European Committee for Future Accelerators, showing the first public images of the quench aftermath, an accident that has become known as the "S34 Incident".
In addition to these images, there are suggestions that there may be no particle collisions next year. Although the most recent report doesn't appear to back up these plans, and replacement parts have started to arrive at the facility (above), it looks like the first collisions probably won't happen until July 2009 at the earliest (that's four months later than previously estimated)...
[caption id="attachment_21898" align="alignleft" width="250" caption="Obvious damage to concrete, where a magnet has been lifted off its mount (the red boxes) that secured it to the floor (CERN)"]
[/caption]It looks like the September 19th quench between Sectors 3-4 of the LHC ring is now being referred to as the "
S34 Incident
". And what an incident it was. Fortunately nobody was injured during the quench, but the LHC wasn't so lucky. For a rundown of the official account of the S34 Incident, I'll hand over to Robert Aymar's November 28th presentation (page 15):
--Robert Aymar, , page 15.
The first image (pictured above) clearly shows the extent of the concrete damage that occurred during the huge pressure forces generated by the leaking helium, ripping the electromagnets off their supports (the red boxes in the photo) and shattering the floor.
[caption id="attachment_21897" align="alignnone" width="580" caption="Obvious buckling of the accelerator magnets (CERN)"]
[/caption]
In this second image, the extent of the damage is pretty clear. Assuming the accelerator beam-line used to be straight (unfortunately, there is no "before" picture), the violent displacement of a huge magnet (weighing several tonnes) is obvious.
Later in the presentation, Aymar points out that 5 quadrupole and 24 dipole magnets need to be repaired and around 57 magnets have to be removed to be cleaned. This will be a huge task, one that will last many months. According to one eagle-eyed blogger at
High Energy PhDs
, a previous report presented a few days before the Aymar report signalled that there may be no high energy particle collisions until 2010.
Jorg Winnenger outlined two possibilities
for the LHC: 1) Partial operations in 2009, allowing only low-energy particle acceleration to await full-scale repairs through the 2009-10 winter shutdown, or 2) Forget 2009 operations and work toward full-scale experiments in 2010. Aymar's more recent report did not mention these scenarios, simply stating, "
the LHC will restart operation in the next spring
."
[caption id="attachment_21904" align="alignleft" width="250" caption="Early progress: replacement parts were inspected at CERN over the weekend (CERN)"]
[/caption]This might be a little optimistic, as other quarters are
signalling a July 2009 "cool-down" before operations can begin
.
Judging by the mixed signals, we'll have to wait patiently until it is clear as to when the LHC is expected to recover. Either way, it will be a long, painstaking and expensive task that needs to be completed as soon as possible.
I really hope we don't have to wait until 2010 until restart
.
Good luck to all involved in the LHC repairs.
Sources:
US/LHC Blog
,
CERN Photos
,
Stephanie Majewski
,
High Energy PhDs