Saturday, March 19, 2011
Visit to CERN
Last weekend I was able to knock off one of my New Year's resolutions and finally headed off to CERN to visit it and learn more about the Large Hadron Collider, the world's largest particle accelerator. We were told ahead of time to arrive early, bring our passport, and not to wear sandals or opened toed shoes, which all make me think we missed something in the tour, since none of those points really mattered.
Our tour started about 30 minutes after we arrived with a presentation on CERN in general. We learned how it was created, how it was responsible for creating things like the world wide web and medical imaging, and how most Swiss French seem to have no idea what "le big bang" was. The video also showed us what went into building the LHC, which is built in a tunnel 100 meters deep and 27 km in circumference throughout Switzerland and France. In order to build it huge machinery weighing hundreds of tons had to be lowered into the tunnels, while measurements had to be so precise as to take into account the tidal movements of the rocks surrounding the tunnels.
Once the presentation was over, a post doc student explained more of what was going on and brought us more up to date (the video presentation was from 2004). He explained how the protons accelerate to .9999999 (he specified seven 9's) the speed of light and then slam into each other. He also explained the various experiments going on, such as ALICE (A Large Ion Collider Experiment), CMS (Compact Muon Spectrometer) and ATLAS (A Toroidal Lhc ApparatuS), which is the building we would go visit.
After this introduction we walked towards ATLAS, around a huge Epcot center looking structure which our post doc didn't really address, stopping in front of the building, where he showed us a painting of what goes on inside the LHC. The painting was on the wall and life-size, but it was an odd spot regardless. He explained how contact happened between the protons (and lead ions) and what was observable and how.
I should say that our video presentation was about 30 minutes long, while the post doc's 'up to speed explanation' was at least another 30 minutes. We then spent a good hour outside looking at this painting. We did, however, get some interesting questions, with the obligatory one about black holes. I found it odd that he didn't seem to have a clearer response to this, but rather asked where the person had heard this before and then rambled on about how all the laws we know in physics would have to change for that to occur. This ended up taking a while also because each response by our post-doc lasted at least 20 minutes. Some of it was interesting, some was just rambling. He obviously loves his job and loves talking about it. I of course asked if he personally believed the Higgs-Boson would be found. I had to prod in a way (he clearly stated his opinion didn't represent CERN's or anyone else's at CERN), but he said he finds it very odd that one fundamental particle could explain all the contradictory laws of physics we have seen. He said experiments done decades ago showed anomalies that convinced researchers at the time of the existence of the Higgs, but he thinks we'll rather have to change some of our laws regarding super symmetry. I might have followed up, but it's very easy to feel dumb when talking there.
After this we headed into ATLAS. Here, unfortunately, we weren't allowed to see the LHC because since 2009 they've been revving it up for experiments. I imagine having tours there could disrupt the experiments (although dropping sandwiches is an occupational hazard, I guess). So we watched people working on the LHC from behind a glass window, which makes me wonder how productive they can be, with countless tours observing them.
Here our guide used a powerpoint presentation to go into more detail about the collider, for instance how the smaller rings act as boosters to slingshot the protons from about 0.98c to the famous 0.9999999c in the LHC proper. He also showed how the Higgs boson should fit into the grand scheme of things in the universe, including muons, gluons and tauons.
This led us to the final 3D presentation, showing people building the LHC and how it looks inside. That ended our 4 hour and 30 minute tour of CERN, where we used no passports and opened-toed sandals would've been fine. I found out later that 2 people tried to sneak out after a few hours, but apparently the gates had been closed behind us. I guess CERN really wants us to learn stuff. There was also one girl who was interested in working at CERN, and seemed fascinated with the tauon.
This was pretty much it. Photos can be seen here and I can cross this one off the list.