A photo tour of the Large Hadron Collider

Back in July, we were fortunate enough to have the opportunity to tour CERN, home of the Large Hadron Collider. In addition to getting some great information on how the machine gets protons up to speeds nearly that of light, and finding out the sorts of physics that scientists hope to find in its collisions, we also got a great view of some of the control rooms and hardware that help keep everything humming along. Unfortunately, with the LHC active, it wasn't possible to actually go down and see the massive detectors that capture the output of the proton collisions, but there's still a lot to see around CERN.

To handle the interest generated by the LHC, CERN has built a new visitor's center to introduce the public to the work that goes on there. For this visit, however, the tour started across the street, next to the CERN gift shop (yes, it has a gift shop).

CERN has been in the business of smashing atoms for several decades now, and reminders of its past show up in many areas of the center. I'm not sure what this is, but its shape evoked that of the new CERN visitors' center, which rises behind it.

Other hardware doesn't quite get this honorable treatment. This bit of hardware was resting outside the facility in which the LHC's magnets are stored and tested. Again, its function isn't clear, but it was obviously the wrong size to link up with any of the pieces being used in the LHC.

Inside, however, the hardware was cutting edge. The accident that occurred during the LHC's start-up depleted the supply of replacement dipole magnets, and CERN is refreshing its stocks. Each magnet is tested extensively under operating conditions, which means lowering them to near absolute zero using liquid helium.

Lots of customized hardware appears to be needed to control the conditions that the magnets will face during operations, and to read out the performance of the hardware being tested.

The magnets themselves are the product of one of the many international collaborations that built the LHC. As the labels here indicate, these magnets were produced by a combination of the KEK physics labs in Japan, and the US' Fermilab. The orange tubes are quadrupole magnets, which help shape the beam as it circulates through the LHC.

Blue tubes hold dipole magnets, built by a collaboration led by Brookhaven National Lab. They help steer the protons around the machine's circumference. But far more than protons need to go through each segment—power, refrigeration, and control electronics all need to be in place, and they need to be built to survive at temperatures near absolute zero.

It isn't just that the hardware has to be tough; it also has to be flexible. As it's cooled, each segment contracts by about four centimeters, so everything inside has to have joints that can flex accordingly. The power supply travels across the structure in the center, where the basket of individual wires allows the hardware to expand and contract.

The LHC's hardware isn't the only thing that has backups; most of the facilities we saw were in close proximity to warehouses that also stored equipment ready to be used if needed. So, it wasn't uncommon to emerge from an ultramodern control room and behold a set of dusty hardware of mysterious purpose.

Old accelerator hardware isn't the only thing kept around. At the CERN computing center, a rather significant NeXT cube is kept behind a glass cabinet: the world's first Web server, complete with a note asking people not to shut it down.

As we wrote in our overview of LHC computing, one of the surprises of the grid computing effort has been how well the networking setup has performed. So, it was no surprise to find huge amounts of rack space dedicated to linking everything up.

Another pleasant surprise has been the price and performance of disks. The original plan was to have data stored primarily on tape, but cheap disks and distributed storage have worked so well (and done such a good job of feeding the network) that disks have seen increasing use at the CERN computing center.