I am at CERN this week for our regular monthly meetings; this time the focus is on ensuring the readiness of the reconstruction software and the various physics analysis groups for analyzing data. According to the current schedule we should see some collisions toward the end of the year, and we have to be ready to start analyzing data on Day 1!
On the software end, we are planning to release an updated version of our reconstruction software within the next week; the aim is to use this version for the first round of data taking. As I wrote in an earlier post, the ATLAS reconstruction software has over a million lines of code, so it is a non-trivial task to make sure that all aspects of the software are working as expected. This validation process can easily take a month or two, and if we find problems we will apply patches; hopefully, all the major bugs have already been found and fixed!
The Physics analysis groups are doing a walk-through of their analysis software and techniques. This is especially true of Physics topics that will be studied in the early days; they are undergoing last-minute reviews to make sure that all bases are covered. Since first running is scheduled to be at lower collision energy than we were originally expecting, some studies need to be re-examined to see if the analysis techniques are sensitive to the change in energy. We are testing our software and producing Physics results with cosmic rays (see Figure 2 in a previous post), but data from collisions is the real thing.
Not only were there formal meetings, but you also see a larger number of small groups of physicists holding impromptu meetings, in the coffee area or huddled around their laptops. I have been coming to CERN for about three years now, and I notice a definite buzz in the air; people appear more rushed; there is a certain sense of urgency.
In my career, I’ve been lucky enough to have worked on experiments (where I played an instrumental role on the hardware or the software end of things) when they were starting to take data. It is a very exciting time but also very chaotic and stressful; the experts are over-worked and sleep-deprived – almost like new parents!
– Vivek Jain, Indiana University
p.s. I forgot to mention that people have also been meeting to discuss how to upgrade the detectors for the time when the LHC beams become very intense (a few years down the road).