FAQ: When do the experiments happen?

One common cluster of questions I get asked is about when do the experiments at CERN actually happen. Are collisions still going on? How often do they happen? What, you worked at CERN until when yesterday? Don't you get holidays off?

Well, grad students and holidays don't exactly . . . meet up particularly often . . . but I digress.

Yes, collisions are still happening frequently in the LHC and its detectors. When the LHC is running in physics mode, those collisions happen about every few hundred nanoseconds or so. Of course, the LHC must be running in physics mode for this to occur. The LHC is a new machine, and is therefore being tested and calibrated right now. While the LHC controllers are testing things, there are no collisions going on, and the four detectors shut down much of the equipment and work on testing things themselves. This is necessary to protect the sensitive and expensive equipment of the detectors while the LHC controllers are tweaking things.

In Paris Again, part 2

Wait, you say, there's more wonderfulness to be told of this trip? Ah, I must confess that while the happy recollections are all made, the story is not yet fully told. The full story must include the arriving at and departing from the fair city.

I have two methods by which I can travel between Geneva and Paris, by plane or by train. The train is noted for it's consistency; SNCF runs trains with varying speeds and numbers of stops between Paris and Geneva daily, regular as clockwork and with prices equally independent of the convenience of the train. Regardless of the day of the week or the time of the day, the train costs about 80 euros (~$105) and will take four hours to get between the cities. Traveling by air is shorter in time and more variable in price. In particularly, a Friday morning flight to Paris on EasyJet cost about $60 when booked in advance, while the return flight on Sunday night cost about $100. So I opted to fly, thinking at least then I would spend less time confined in a seat for the same amount of money.

In Paris Again, part 1

Well, I couldn't very well only spend three hours in the Louvre, now could I? That just isn't nice. Also, as a long-term resident of the EU and in my early twenties, I was eligible for free entry or a discount at every place I visited, and I wanted to take advantage of that while I could.



Musee de Louvre: I had already seen (and posted on) seeing the Louvre's signature pieces like the Mona Lisa, the Nike of Samothrace, and the Venus di Milo. This time around I spent five hours in the museum and walked through the Egyptian, Babylonian, and post-Baroque paintings. I also got to see, in person, my favorite creature from my art history class, the lamasu. See the five legs?

Je Souhaite

Trying to learn a new language makes you appreciate little triumphs, such as the first time you held a successful conversation with a stranger about the weather. For me, that happened Friday night. I was catching a tram into Geneva, and a little old lady asked me if I was cold, as it was raining a bit and I had no coat. I said no, she mentioned the dropping temperature, and I blamed it on the rain. I said perhaps six words, but they were an appropriate six words, so some communication occurred.

Still, as I sit in the midst of dozens of native French speakers, speaking and laughing, cracking jokes that I can't understand in French and they cannot translate to English, I can't help but feel wistful. It would be nice to enter a real conversation and be able to say something meaningful.

if (wishes == true)
{
std::cout << French << std::endl;
}

Geneva, the first weekend in June

When I began working with my adviser, it was a foregone conclusion that I would eventually move to Geneva, Switzerland and work at CERN. Every grad student at my university who worked in my experiment did. It was only the details of when exactly I would leave and how long I would stay that were undecided. Truth be told, I was in no particular rush to pack up and move. Yes, living in Europe would be awesome, but one to two years is too long to just put life on hold behind you. On that time range, I would be leaving behind friends and habits and hobbies that would require rebuilding in a foreign country, and then rebuilding again when it was over and I returned to the US.

The decision of when exactly I would go was lurking on my mind when my adviser emailed me into his office for a chat in February or March 2009. After checking up on my current research and my progress towards my preliminary exam, he asked me if I was interested in traveling during the summer. Particle physics is an international field, and grants often include funds to let grad students travel to schools and conferences once a year. I was already going to a summer school, but my adviser suggested an additional trip. He wanted me to go to CERN for a week or two, to complete the paperwork registering me a researcher there, meet the half of the group stationed there that I hadn't met yet, and sit in on a few meetings to get acquainted with things. Plane tickets and accommodations would be covered by my university.

A most-expenses paid trip to Europe for ten days? I went.

So on the last day of May I arrived in Geneva, seeing continental Europe and CERN for the first time. I spent the week filling out forms and learning my way around CERN and writing computer code, but the weekend I had free. I tagged along with my adviser as he caught a train from Gare Cornavin, and I spent a few hours wandering around downtown Geneva.

The city of Geneva sits on the tip of Lac Leman, the very corner of Switzerland that juts into France, where the Rhone River leaves the lake. Along the shores of the lake are parks and wharfs, statues and fountains, a giant clock set in the ground planted with flowers and the Jet d'Eau shooting water into the air. On that first weekend in June, somewhere in between spring and summer, I walked along the east side of the lake and watched the ducks and swans and admired the beds of roses coming into bloom, red followed by yellow followed by pink followed by peach.

This past weekend, I went back and did it again, to commemorate the one year since I had first come to Geneva.

Apartment-grown strawberries

I know, I shouldn't have, not if I intend to recover from all the cake-baking. But don't my little strawberry plants look so proud of themselves?

C++ bug hunting

I remember well my first experiences with computer programming. I was required to take a lab class on Maple as a freshman in college, and it was rather frustrating. I'm surprised my TA was still being civil to me after all the dumb questions I asked him all semester. I succeeded in "writing" a for loop (copied an example from the help files) for the final exam for that class, and considered that the triumph of my freshman year. I swore to myself I would not pick a branch of physics that would have me staring at a computer screen all day.

As the unromantic description of what I do at work all day is now "write computer code," I have eaten those words many times over. I have also, thankfully, gotten better at computer programming. I like it now; a lot of programming is like solving a logic puzzle. I can now claim a working relationship with C++ and SQL, a handful of successful encounters with Python, and an acquaintance with Java. I'm not a full-fledged programmer, but I can write code for my analysis.

Of course, that also means a lot of my time spent "researching" is spent researching why my code is not doing what I expected/planned on/ thought I told it to do.

The easiest problems to deal with are the compiler errors. After I write a piece of code, the compiler translates the human-readable program into a computer-readable set of instructions, which can then be run by the computer. Unless, of course, I wrote something the compiler cannot translate. Then it spits out error messages detailing, in compiler-speak, what it couldn't read and where to find it. This normally happens because I mistyped something or didn't provide some part of the program with quite the information it expected. This also barely counts as an error because these issues are normally fairly easy to fix. This is not what is meant by the term "debugging."

Of course, sometimes I mistype something in a way that still makes sense to my compiler. This often happens when I get variables names or other labels mixed up. Then the code will compile and execute just fine; it will just give me nonsense. I then get to spend a merry hour or two (or three days plus an hour going over code with my adviser) double-checking my variable names and trying to sort out where the insanity came from. This is also not what is meant by the term "debugging."