CERN Accelerating science

Focus on the Run Coordinators of the LHC Experiments (Part 2)

by Panos Charitos

Following two years of maintenance and consolidation work, the Long Shutdown 1 officially ended on 5 April 2015, when the first proton beams circulated the LHC. Now the LHC experiments are getting ready to operate once more and record the first collision data. In this task, the role of the Run Coordinators is crucial, as they manage the commissioning and operation of the detectors, as well as all data-taking operations.

In the previous issue of the PH Newsletter, we introduced the Run Coordinators of CMS, LHCf, and ALICE. This time, we will get to know the Run Coordinators of ATLAS, TOTEM, and LHCb, who talk about their work and the challenges that they have to face.

Alessandro Polini

After his academic studies in Physics in Bologna, Alessandro moved to Hamburg in 1993, to work on the DAQ and trigger of the Forward Muon Spectrometer of ZEUS, one of the two large experiments at the HERA electron-proton collider at DESY. He originally planned to stay a few months, but ended up staying until the HERA accelerator finished its programme in 2007. During those years at DESY, he studied diffractive physics and worked on several systems from the new Silicon Microvertex, to the Uranium calorimeter, and the ZEUS Trigger. After HERA was shut down, he moved to CERN, joining, along with his colleagues from Bologna, the ATLAS collaboration, working on the Muon Spectrometer and its Detector Control System. He followed closely the Run 1 data taking, becoming muon Run Coordinator for the period 2011-2012. When asked about what he likes in his work, he says he has always enjoyed and found particularly stimulating the environment of international collaboration and the research in experiments at the high-energy frontier. Besides experimental physics, he likes music, plays piano and synthesizers, enjoys cooking and walking in the mountains. As a Run Coordinator of the ATLAS experiment during the first Long Shutdown and the restart in 2015, he followed the re-commissioning of the detectors and the preparation of data taking. He feels very satisfied with such work, which he likes comparing to the one of a music director who, in view of a new big project, prepares and rehearses with all of his fellow musicians to bring the whole ATLAS to work perfectly, having his mind always open for new ideas and discoveries. Whatever the LHC and Nature is or is not going to reveal during Run 2, it will be an honour having contributed to this phase.

Mario Delle

Mario’s particle physics career started at the University of Munich, LMU, with his diploma and PhD thesis work on optimisation and calibration of the  Monitored Drift Tube chambers (MDT) for the ATLAS Muon Spectrometer.  After obtaining his doctoral degree in 2000, he moved to Yale University as a postdoc working on the Muon g-2 experiment at Brookhaven National Laboratory (BNL), focusing on data analysis. After returning to CERN in 2003 as a research fellow, Mario chose to join the TOTEM experiment, appreciating the complementarity of its physics programme to that of the other experiments. Following the end of his fellowship, he stayed in TOTEM as CERN staff member. Given that TOTEM is a small collaboration, every member has the opportunity to be involved in all aspects of the experiment.  Thus his tasks have ranged from participation in the development of the physics programme, to test beam coordination before the start of the LHC, and finally run coordination.

The TOTEM experiment is characterised by a very particular configuration, with tracking detectors mechanically integrated partly in the forward region of CMS, and partly in Roman Pots – moveable LHC beam pipe insertions up to 220 metres away from Interaction Point 5. Operating this apparatus safely and to its fullest potential requires strong ties with the partner experiment CMS and with the LHC machine groups. Furthermore, a major part of the TOTEM physics programme is accomplished in dedicated beam time with special accelerator settings that need to be defined in cooperation with machine experts and then coordinated with the other experiments in the LHC Programme  Committee. In TOTEM, this interface role is part of the run coordinator duties that Mario has carried out since the creation of this position in 2008.  On the technical side, Roman Pots are similar to collimators in their capability to move towards the high-intensity LHC beams, exposing the machine to the risk of damaging beam losses in case of a too close approach. These risks and their mitigation strategies are discussed in the LHC Machine Protection Panel where he is responsible for his experiment's inputs to the LHC interlock system, designed to extract the beams automatically from the accelerator ring if a control system detects a dangerous situation. The collaboration-internal aspects of his Run Coordinator role include the  organisation of the data-taking crews in the TOTEM control room at IP5 and  in the LHC control room (CCC) where the Roman Pot movements are executed  (very often by himself). Until the first Long Shutdown, most physics data have been collected in dedicated beam time with often uncertain planning and requiring the presence of the system experts rather than regular shift crews.  Hence the coordination task in TOTEM has been characterised by flexibility and very short-term planning. Between data-taking operations, due to the absence of regular shift crews, one of his tasks was to provide a 24 h on-call service as official TOTEM contact person for the LHC control room and the  other experiments. During the Long Shutdown, he participated in the consolidation and upgrade of the Roman Pot system to make it compatible with operation at higher luminosities and pileup levels.

In Run 2, the cooperation with CMS in view of common data-taking will be strengthened, implying also an intensification of the exchanges with CMS run coordination. For the CMS-TOTEM high luminosity forward physics programme, a common project, "CT-PPS", has been created, having its own Run Coordinator.  This task has been taken on by Mario, too. Together with his collaboration, he is looking forward to the new challenges of Run 2.

Patrick Robbe

After studiying  in France at the Ecole Polytechnique in Paris and at the Ecole Normale Supérieure in Lyon, where he obtained his Master in Theoretical Physics in 1999, Patrick joined the BaBar experiment at the laboratory for Particle Physics of Annecy for his PhD thesis. He studied the decay of B mesons into two charm mesons (decays of the type B → D D K) and measured their branching fractions.

He defended his thesis in 2002 before moving to the LHCb experiment as CNRS researcher in 2002. As he explains: "I wanted to continue in the area of B physics, and joined the Laboratoire de l’accélérateur linéaire in Orsay. I took part in the building of the calorimeter electronics, in particular the electronics devoted to the hardware trigger (or Level-0 trigger) and its commissioning. This is why, I was involved in Run 1 data taking". Concerning physics analysis, he worked and supervised PhD students on the first LHCb J/ψ cross-section measurement and on the measurement of CP asymetries in B → DK* decays that are sensitive to the θ angle of the CMK matrix. Ηe is also teaching particle physics at the Universite of Paris-Sud in Orsay.

Patrick started his two-year mandate as LHCb Run Coordinator in January this year and he will be assisted in his role by Federico Alessio (PH-LBC) who is the deputy Run Coordinator. The main challenge for Run 2 at LHCb is to collect data efficiently in very stable conditions, thanks to a new calibration procedure which will run online. The deployment and usage of this new feature will be a major event of the restart of data taking. Moreover, it is important that all LHCb collaboration members have a chance of participating to the data taking of the experiment at the pit. As he adds: "It is especially interesting for students, because they have the perfect opportunity to learn a lot about the detector and the data they use for their data analyses. We will give a special attention to shifter trainings for this reason".