The sun has already set over Geneva when I finally walk out from the ATLAS control room. We have been waiting for beams to be injected into the machine since the early hours of the afternoon, but without much success so far. First a issue with high voltage in one of the accelerator sectors, then some problems in controlling the cooling temperature, and finally a UFO dumping the beams (not what you are thinking of – rather a microscopic dust particle in the beam pipe, creating instabilities in the beam orbits). Just a regular day for the most ambitious particle accelerator mankind has ever built, but a pretty boring afternoon for our entire shift crew.
With the 50 ns data-taking now half-way over, the ATLAS control room is no longer crowded as it was back in early June, when rivers of champagne were flowing out to celebrate the first Run 2 milestones and Discovery Channel cameras were filming physicists in their natural habitat. Now that more routine data-taking has been established, only the six shifters are there permanently, plus a few experts to assist them… and the Run Manager, which is me this week.
Luckily the messages from the LHC team keep us awake: they regularly announce beams “very soon”… and we always believe it.
The Run Manager acts as a layer between the Run Coordinators and the rest of the team, making sure the plan of the day is respected and steering ATLAS operations towards a happy ending. But what if there are no operations to be steered? The excitement for us starts with the first hint of proton collisions – before that, we need to get ready and then wait patiently.
Luckily the messages from the LHC team keep us awake: they regularly announce beams “very soon”… and we always believe it. Under the vigilant eye of the Shift Leader, the trigger shifter keeps on checking constant particle rates, the shifters from the sub-detectors (the inner detector, the calorimeters and the muon systems) stare at green flags, the shifter at the Run Control desk enjoys the flux of harmless warning messages, and the Data Quality shifter gets ready to monitor the goodness of the data we might be collecting tonight.
Two more hours, and they will all be released, while the next shift crew comes in. Only the Run Manager – now sitting at the CERN restaurant nervously checking her phone – had better stay, to make sure all parameters are set correctly before a long fruitful run starts. In such a complex detector as ATLAS, every configuration has to be checked by multiple pairs of eyes; we can’t afford the luxury of making mistakes.
I am always surprised by how little competition reigns here in the control room. We are all part of this huge wonderful mechanism, that wouldn’t work without the tiniest piece – and we feel it. We are always happy to help new people getting started (so that they may eventually cover some night shifts, a privilege often reserved for students…) and ensure that they are never ashamed to ask trivial questions. I would say it’s like being part of a funny, weird family… if only it would not certainly condemn me to the eternal mockery of my colleagues! Friendships have been built over coffee, eating the Sunday croissants together (a small reward for being here over the weekend), and during the daily rushes to get our slides ready for the next presentations. Long days and long nights that we hope will bring new exciting discoveries.
The sunset has now made room for a warm summer night, but still no beams are circulating in the machine. I will need to call the CERN Control Center to ask what their plans are. It’s late but I don’t feel that tired. With a sigh and a smile I walk back to the control room, while the sky over the Alps turns into pink and then lilac and then blue.