Between given lectures, attending meetings, organizing workshops, supervising analyses and writing notes, I managed to squeeze in some real experimental particle physics time: A weekend of shifts at the CALICE test beam at the CERN SPS. OK, admittedly my wife complained bitterly that I take the weekend for that, but things have been really a bit crazy lately, so that was the only time I could squeeze in.
And yes, it was worth the three day trip to CERN (combined with a meeting this afternoon, some habits are just too hard to break): Of course there is the obligation part: I’m hoping to do a little bit of analysis on the data myself, and two of my students have a special setup running in that beam, so I felt I have to do my share. But then, test beam is something I also really enjoy: This is really experimental particle physics at its best! Of course it is not hunting the Higgs or trying to observe rare reactions showing hints for new physics, but you are never so close to a complicated high energy physics detector and to the details of operating particle beams as during test beam campaigns. Plus, things get really experimental: To measure muons for calibration also in the lower edges of our calorimeter, we installed some dedicated trigger scintillators: A quick access into the beam enclosure, armed with a power drill to fix a rail to the back of our detector, and a scintillator held in place by black scotch tape and a chain fixed by cable ties – real HEP style.
And since the data taking in the past week was going really well, we even had the chance to play a bit last night: We took a sample of charged kaons, in addition to the pions we usually use to test our calorimeter. The charged kaon consists of an up and an anti-strange quark, and decays after a few (in case of the high energies we have, after some one hundred) meters in flight. Mostly into a muon and a neutrino or a charged and a neutral pion. But with 5% probability also into three charged pions. Those will hit our calorimeter close together, and maybe, just maybe, we can separate them into three particle showers using the high granularity that we have. No idea if this will work, but I’m eagerly waiting for the data to run through the processing to take a first look. But that will have to wait for tomorrow. Now, after landing at Munich with the last flight back from Geneva, I’m just a short train and cab ride away from home, and some really much needed rest.