by Panos Charitos. Published: 08 July 2012

Xavier Lopez is this month’s period run coordinator of ALICE, a highly demanding but also challenging role. Explaining his current role he says, “I have to make sure that everything works properly in the ALICE control room.” Among other things he must ensure that the shifters are able to carry out their duties properly, give instructions related to the data taking, and also to make sure that the LHC beams would not harm ALICE’s detectors. Being a period run coordinator means that there are so many things to take care of that there is very little free time. Responding to my question about his free time he laughs and mentions that “It has been a week since I became a technical coordinator and so far it’s been hard to have a full night’s sleep.” He adds that it is very important to follow the change of shifts, particularly to ensure that everything runs smoothly.



Xavier Lopez the new period run coordinator of ALICE


After spending the day in the control room, he summarizes the day’s activity for the daily Run Coordination meeting. The summary includes what happened in the machine the previous day and what is the ALICE data taking status as far as their efficiency. This means that Xavier, as every other Period Run Coordinator, has to attend a meeting with the LHC group that every morning, seven days a week, for a month. There is also a weekly run coordination meeting during which “is discussed where do we stand in terms of data taking. We also discuss next week’s plan. For example we need to plan in advance when there is a technical stop, which allows us to go into the cavern for detector maintenance.”

Xavier has been working for a long time in one of the ALICE sub-detectors as a deputy of the muon trigger system. This experience helped him “to get the basic knowledge of data acquisition and detector control system.” Of course “it is mandatory to have an experience of general shifts at ALICE in order to know how to start or stop a run, put the detector in ready mode and take a shift if someone is missing in the control room,“ and then“ you are closer to understand how ALICE works, what you expect the LHC to deliver and in which condition.”

Xavier did his PhD in Clermont Ferrand and then moved as a post-doc to GSI in Darmstadt; there he worked for the FOPI collaboration, which studied heavy ion collisions at higher baryonic density and lower temperatures than the ones we see in ALICE. Then Xavier started working on ALICE. He now got a “Maître de Conference” position in Clermont Ferrand, where he teaches while at the same time continuing his work with ALICE.

Regarding his physics involvement, Xavier participates in the analysis of data taken by the muon trigger and is also involved in the analysis of the Upsilon in the pp-collisions. He co-supervises a Ph.D. student working on the Upsilon analysis in lead-lead collisions. Their goal is to be able to measure a new Upsilon nuclear modification factor and to explore whether there is suppression in central collisions with respect to peripheral ones in the forward rapidity region.

Xavier notes how lucky he was to attend last week’s seminar on the Higgs boson and how exciting it is to see this resonance-like peak that was shown by ATLAS and CMS. Regarding ALICE he thinks that it is a fantastic detector, which allows us to study and understand closer the properties of the Quark Gluon Plasma. “I think that ALICE has many things to tell us about this new state of matter!”


Xavier Lopez at ALICE P2 where we interviewed him