Geneva Metropolitan Area
Personal Interests: - Management of large technical projects in an international environment - Research & Development - Technology transfer and industrialization Specialties: - Magnet design and technology - Applied superconductivity and cryogenics - Large physics instruments
- Contribution to brainstorming on the future of accelerator technologies, aimed at developing and updating medium and long-term R&D plans in the areas of superconducting magnets, cryogenics, vacuum, and machine protection. - Prospection and assessment of opportunities in the development of innovative magnet systems for physics experiments, in collaboration with CERN experimental physicists and detector magnet experts, e.g., SHiP (Search for Hidden Particles) and BabyIAXO (reduced scale demonstrator for International AXion Observatory) experiments. - Oversight of design and development of an energy-efficient spectrometer magnet based on innovative MgB2 conductor technology indirectly cooled by gaseous helium at about 20 K. - Oversight of CERN high-performance Nb3Sn conductor R&D plan; development of strategic collaborations with non-EU member states such as Japan (KEK, High Energy Accelerator Research Organization) and Korea (KFE, Korea Institute of Fusion Energy). - Participation to various Steering Committees of external collaborations, e.g.: CERN-ITER Implementing Agreements 24 (high voltage engineering) and 25 (metallurgical and material testing), member of Fusion Technical Advisory Group (FTAG) to the United Kingdom Atomic Energy Authority (UKEA), member of review panel for SupraFusion Research Project 2 on “HTS Conductors”, that is part of the French Priority Programs and Equipment for Research (PEPR). - Regular participation to technical meetings and reviews of various domestic projects in China for the development of fusion technology, such as CRAFT (Coordinated Research Facility for Fusion Technology), BEST (Burning plasma Experimental Superconducting Tokamak) and CFEDR (China Fusion Engineering Demonstration Reactor), organized by CASIPP (Institute for Plasma Physics of the Chinese Academy of Sciences).
- Management of one of the largest CERN Groups with ~100 staff, ~50 students and postdocs, ~100 externals and ~10 large and unique R&D and production workshops as well as test facilities. - Support to operation, maintenance and consolidation of resistive and superconducting and magnets, current leads and ancillary systems in the CERN accelerator complex. CERN has an inventory of ~5000 normal conducting magnets, and ~9000 superconducting arc, interaction region and corrector magnets. - Contribution to the High Luminosity upgrade Project for the Large Hadron Collider (HL-LHC): management and execution of several Work Packages (11 T dipole magnets, interaction region magnets and superconducting links), involving 8 worldwide collaborations for a cost of ~300 MCHF. Responsible for the timely delivery of compliant magnets and cold powering systems. HL-LHC will see the first use of Nb3Sn magnets in a particle accelerator and the first large-scale application of MgB2 power transmission lines. - Developed and implemented a recovery plan to address the performance limitation/degradation of full-length (> 5 m) Nb3Sn dipole and quadrupole magnets for HL-LHC. The plan called for a comprehensive root-cause analysis and the manufacture and test of additional full-length quadrupole magnet prototypes to validate recovery actions. The last quadrupole magnet prototype, integrating all improvements, was successfully tested in Summer 2023 and paved the way to the of production of the 8 units needed for the project. - Operation, maintenance and upgrade of CERN’s infrastructures and test facilities to preserve and expand their unique capabilities. Preservation and development of competency poles to consolidate in-house expertise and form the central nodes of collaboration networks at CERN and with partner institutes. - Development of innovative diversification programs to valorize know-how and infrastructure.
- Assisted Group Leader in all administrative and management functions regarding operation, planning and resourcing of the TE-MSC Group and in the definition of the strategy for the Group evolution. - Participated to the organization and follow-up (managerial and technical) of TE-MSC Group contributions to maintenance and upgrade activities for the CERN accelerator complex, incl.: Long Shutdown 2 of LHC (LS2), LHC Injector Upgrade (LIU), High Luminosity LHC upgrade (HL-LHC) and other projects and studies; share this work with the Group Leader, focusing especially on the HL-LHC Work Packages under TE-MSC Group responsibility: Interaction Region Magnets (WP03), Cold Powering (WP06a) and 11 T dipoles (WP11). - Contributed to the supervision of HL-LHC WP11 activities; in particular, initiated a Task Force to review critical magnet assembly processes, which addressed issue of excessive transverse force on coil straight section during collaring and culminated in July 2019 with the successful test of the first, full-length, 11 T dipole magnet, relying on high-performance Nb3Sn conductors. - Contributed to the organization, planning and follow-up of HL-LHC WP6a activities, which concern the development of an innovative system relying on the first large scale applications of superconducting MgB2 cables to supply currents to HL-LHC interaction region magnets; a critical milestone was achieved in June 2020 with the successful test of a 60-m-long system demonstrator, including 4 x 18 kA, 3 x 7 kA and 12 x 3 kA MgB2 cables, which operated reliably with Nb-Ti at 4.2 K, MgB2 at 25 K and HTS REBCO at 50 K . - Contributed to the development of an R&D Strategic Plan for the TE-MSC Group, by defining main objectives, timeline and associated resources; these inputs served in the definition of the High Field Magnet program that was eventually approved by the CERN council in June 2020.
- Supervised development of strategy and plan for ITER magnet assembly preparation and execution; responsible for defining scope and complexity level of magnet assembly processes; responsible for identifying executing entities and for developing procurement plans engaging ITER partners; responsible for defining and procuring mock-ups for qualification and training/certification; supervise tender document preparation. - Responsible for developing helium risk register for all magnet systems and for developing helium leak risk mitigation measures and helium least test procedures that flowed down ITER vacuum hand book requirements to all magnet procurements; this led to significant revisions of helium leak strategy for Toroidal Field coil structures and magnet supports that had to be negotiated with Japanese and Chinese Domestic Agencies and their suppliers. - Supported Magnet Division Head for Division organization, resources deployment and planning, firefighting for in-cash and in-kind procurement issues, handling of technical and managerial interfaces within ITER Organization and with ITER Domestic Agencies. - From February to December 2016, supervised the Procurement Arrangements of the toroidal field (TF) coils with Europe and Japan, of the structures for the toroidal field coils with Japan and of the magnet supports with China; launched a number of technical and managerial recovery actions to strengthen monitoring and Quality Assurance/Quality Control, to speed up documentation finalization and decision making process and to improve collaboration with the Domestic Agencies.
- Responsible for the in-kind procurement of the superconducting Cable-In-Conduit Conductors used in the manufacture of the magnet system at the heart of the International Thermonuclear Experimental Reactor (ITER); the conductors amount to 650 M€ (half of the magnet system cost) and are provided by six ITER members (China, EU, Japan, Korea, Russia and the USA). - Supervised the development and implementation of the technical specifications and QA/QC requirements for the 11 ITER conductor Procurement Arrangements; monitored industrial productions around the world; followed up schedule; reviewed/approved change requests, non-conformance reports and final acceptance tests. - Oversaw a ramp up of the world production of Nb3Sn strands from 15 to 100 tons/year over 5 years to meet ITER needs (685 tons) and the successful entry of 3 new suppliers into the market (in China, Korea and Russia); oversaw a successful crash program to resolve electromagnetic/thermal cycling degradation issue for the conductors of the ITER Central Solenoid, the largest and most powerful Nb3Sn coil ever designed to sustain 60,000 pulses to a maximum field of 13 T. - Supervised the in-kind procurement by China of the ITER feeder system (50 M€), which include over 45,000 manufacturing drawings and 600,000 parts and many interfaces with other systems to bring current, cryogens and instrumentation to the ITER magnets; the production of the first component was successfully completed in July 2017. - Supervised the fund procurement by ITER Organization of the instrumentation for the magnet system (over 20 external contracts worth 45 M€). - From June 2015, supervised the design, development and fund procurement (50 M€) of the in-vessel coils (IVC), a critical system made up of water-cooled, MgO-insulated, Cu conductors mounted inside the vacuum vessel; developed an action plan that led to a redesign of the coils and their support system; launched in December 2016 the procurement of the IVC conductors.
- Manager of the Next Europe Dipole (NED) program, a Joint Research Activity of the Coordinated Accelerator Research in Europe (CARE) project, funded by the EU (Framework Program 6). - As part of NED, supervised a collaboration of eight European Institutes: CEA in France, CERN, CIEMAT in Spain, INFN-Genova and INFN-Milan in Italy, RAL in the UK, Twente University in The Netherlands, and Wroclaw University in Poland aimed at developing the next generation of particle accelerator magnets. - The NED collaboration successfully developed a high performance Nb3Sn wire and carried out the design analyses of a 88-mm-aperture, 15-T dipole magnet for LHC upgrade. - Manager of a CEA-funded R&D program aimed at manufacturing a technology-demonstrator quadrupole magnet model relying on Nb3Sn cables. - The CEA program was carried out in collaboration with industry (Alstom/MSA) and other French National Laboratories (Laboratoire de Céramique et Matériaux Avancés, Le Ripault, and Institut Européen des Membranes, Montpellier). - Co-author of a patent on an innovative cable insulation system for Nb3Sn coils. - Supervised a graduate student who developed a novel technique to simulate quench precursors using a single-mode diode laser (first experiment on firing a quench using optical power). - Supervised a graduate student who studied the parameters influencing interstrand coupling currents in Nb3Sn Rutherford-type cables. The recommended configuration is a cable made from un-plated strands and integrating a thin stainless steel core between the cable layers. - Taught lectures at École Spéciale de Mécanique et d'Électricité (France).
- Responsible for the design and manufacture of a magnetic measurement equipment to assess the field quality of LHC arc quadrupole magnet prototypes designed and built at CEA/Saclay. - Developed a comprehensive formalism based on complex notations to describe magnetic fluxes picked up by rotating coils and assess/diagnose measurement errors. - The measurement equipment was successfully commissioned in July 1995.
- Senior advisor to Magnet & Superconductors and Magnet Tests & Measurements Groups. - Participated to the follow-up of the industrial production of the 1232 arc dipole and 400 arc quadrupole magnets for the Large Hadron Collider (LHC) project. - Carried out detailed reviews of designs, manufacturing procedures, production data and test results to analyze and trace back the origin of observed deviations and/or to assess the impact of known discrepancies. - Oversaw several magnet autopsies. - Led an effort to inventory sources of parasitic fields around the LHC machine and to assess their potential effects on beam optics. - Carried out a comparative analysis of the designs, assemblies and performances of the first generation of full-size LHC dipole magnet prototypes. The analysis provided recommendations on how to improve the mechanical design to make it more robust and less sensitive to assembly discrepancies during large scale production. - Supervised a graduate student who developed detailed 2D and 3D finite element models of the LHC dipole magnet coils taking into consideration the various friction coefficients at the origin of the observed hysteresis in the coil stress-strain curves.
- Led a group of scientists defining test procedures and analyzing test results of full-size superconducting magnet prototypes for the Superconducting Super Collider (SSC) project. The group was responsible for assessing conformity of magnet performance to the design, determining the origins of discrepancies and developing models explaining observed behaviors. - Assisted with technology transfer and with monitoring of design, manufacture and test activities at the various industrial partners involved in superconducting magnet production for SSC. - Carried out detailed studies of the mechanics of SSC dipole magnet prototypes showing the importance of controlling coil manufacturing process to achieve a suitable level of coil pre-compression during assembly and after cooldown, and of optimizing coil clamping structure in both radial and axial direction to limit deformation and prevent ratcheting during energization. - Studied the behavior of SSC dipole magnet prototypes as a function of current ramp rate. Observed 2 different behaviors. Type A behavior is characterized by a rapid and monotonous decrease of the quench current, associated with large losses and severe magnetic field harmonics degradation. It is driven by large interstrand coupling currents arising in the magnet coils. Type B behavior is characterized by a rapid decrease of the quench current at low ramp rate followed by a near stabilization at higher rate, associated with low losses and small magnetic field harmonics degradation. It is driven by large current imbalances among Rutherford-type cable strands. - Led a series of experiments demonstrating the existence of a new mechanism, based on “trapped currents,” responsible for the time dependence of magnetic field harmonics in superconducting particle accelerator magnets energized at low and constant current (at the origin of the so-called “snap back” effect). - Taught lectures at UT Austin, UCLA, University of Chicago.