The Shift Leader
The efficient operation of the experiment relies on a well-established hierarchy in the ALICE Run Control Centre (ARC). Different tasks are delegated to different types of shifters. First of all, at the heart of ALICE we have the central shifts – Experiment Control System (ECS), Detector Control System (DCS), Data Quality Monitoring (DQM), and Shift Leader (SL). When they face a problem with a detector which they can’t resolve, they contact the on-call shifters, the detector experts who know how to solve specific issues related to their systems. Above all of them stands the Run Coordination team.
Unlike the other three central shifters, the Shift Leader doesn’t have a specific system to operate and control. He is responsible for all the routine operations of ALICE and he ensures that the daily programme of data taking is enforced. Under his supervision everything has to run smoothly and no data should be lost. He is also the one who takes responsibility if something goes wrong.
“Ultimately, we want to take good-quality data and we want to be as efficient as possible. We can lose neither time, nor data. As Shift Leader you have to prepare the experiment for data taking. You have clear and detailed instructions and you follow them in order to do specific tasks.” – says Paraskevi Ganoti, an experienced Shift Leader from the University of Athens, Greece. “You have a number of web pages to monitor. You must be aware of what the LHC is currently doing by following their logbook. One of the most important pages for the Shift Leader is the ALICE configuration tool. Before recording physics data, we have to prepare the experiment – we set the triggers and prepare the DAQ partitions for the different cases – for physics, cosmic or technical runs. We monitor the luminosity set by the LHC, we can set our own luminosity, we control the beam parameters – pretty much everything.”
No one in the ARC acts on his own and the issues are usually resolved after a discussion within the team. Faced with a problem, the ECS, DCS and DAQ shifters notify the Shift Leader, who decides the course of action. If the issue falls out of his competence, he reports to the Run Coordination team. “When there is something that you don’t know, the run manager is there to help. He is the one who knows everything, as well as the Run Coordinator and the Deputy Run Coordinator” – explains Patrick Steffanic, a Bachelor student in physics at the California Polytechnic State University (Cal Poly), USA.
Some of the most important qualities that the Shift Leader must possess is to be flexible, to adapt quickly to new situations and to react fast when circumstances change. As Patrick explains: “I enjoy the challenge of multitasking. It is important to stay calm, to figure out how to get the most amount of data first and then to deal with the rest. The biggest problem that I have encountered was having more than one detector not working properly at once. In these situations it is a bit more difficult to decide what has caused the issue and what actions are to be taken. This is when having previous experience is crucial – knowing which detector you have to fix first or which detectors you may exclude from the run in order to identify and fix the problem without affecting the data taking.”
Both Paraskevi and Patrick enjoy being on shift and see the benefits of spending time in the ARC. “Each time I learn new things about the experiment. Each time I face something new. Since it is impossible to know everything, you are forced to ask and thus to enrich your knowledge” – says Paraskevi. His strongest motivation Patrick finds in a different aspect of being a Shift Leader: “It is great to see the physics runs going smoothly and to feel that you have personally contributed to that. Before you start doing an analysis, you select the runs you want to work with. Having created these runs in a sense, my personal contribution to the recorded data, makes me feel a little bit closer to the physics.”