Hi-Lumi LHC: collisions get brighter also thanks to our Alumni

The groundbreaking ceremony that was held on 15 June officially marked the beginning of works to upgrade the Large Hadron Collider (LHC) to the High-Luminosity LHC (HL-LHC or Hi-Lumi). The upgraded machine will deliver a higher number of proton-proton collisions per second, thanks to the increased luminosity. More collisions means more chances for physicists to investigate rare phenomena and collect more accurate measurements. 

All sectors of research – hardware and software development, theoretical physics, accelerator physics, engineering – have been involved in the project since its very beginning and, as a consequence, many scientists have contributed to its success. Today, some of these specialists have left CERN and are working in other sectors. We have interviewed two of them: Tao, who worked in radiation-hardened Integrated Circuit Design for the data-transmission optical links for ALTLAS and CMS experiments and currently working at Google as a Hardware Engineer; and Liesbeth, who worked as a senior fellow in the Magnets Normal Conducting section of the Technology department and is currently working as a Senior Design Engineer at ASML in The Netherlands.


The HL-LHC is a big project, spreading over many years, and yet each single contribution makes a significate difference. If the specific project you worked on had not been successful, what would have happened to the whole upgrade programme of the LHC?

Liesbeth: My work involved the design, engineering, and follow-up of manufacturing and testing of normal-conducting magnets for Linac4. Linac4 was built to replace Linac2, and is crucial in the delivery of the targeted high luminosity beams in the LHC. To be very specific, I worked on the inter-tank quadrupole magnets, and the transfer line quadrupole magnets. Quadrupole magnets are needed to focus the beam. That means that without my work, the particles would defocus and the quality of the beam would be very low.

Tao: I participated as a radiation-hardened Integrated Circuit (IC) Designer for GBT (GigaBit Transceiver) and Versatile Link projects, which are radiation-tolerant data transmission ICs and links to be installed in HL-LHC. The HL-LHC collects ten times more data than in the current LHC. The collected data, which is at the level of a hundred petabytes, has to be transmitted to the CERN Data Center through these ICs and links during the collisions before being further distributed to other Data Centers and analyzed by the scientists and researchers worldwide. The GBT and Versatile Link projects are a critical part of HL-LHC. Without their success, the collected data, therefore, possible new discoveries, would not be available.


Are you still following what’s going on with your former project now that you are a both alumni? Are you still in touch with your former colleagues?

Liesbeth: Yes, I do try to keep in touch with former colleagues who still work at CERN, for news about the magnets I worked on. I recently read a report on the status of the Linac4. I also still hear from CERN colleagues that have left CERN and have moved to different jobs and countries. Finally, whenever I meet people who have made their career through CERN, we usually have fun comparing our experiences!

Tao: I am still closely following the progress with the former projects, and keep constantly in touch with former colleagues. I also got opportunities to meet some former colleagues. Like at the Topical Workshop on Electronics for Particle Physics conference in 2017 which was in Santa Cruz, California, close to my current working office. I had the opportunity to talk to former colleagues working on the former projects.


Taking part in such an ambitious project has probably left a huge legacy on your professional career? Is it frustrating having had the possibility to take part only for a short period of time or has it been the leverage for a continuation of your career in other fields?

Liesbeth: It would have been great to have been able to continue my work and take part in the commissioning of Linac4. On the other hand, I am truly a computational scientist, which was not so much part of my work at CERN. After my fellowship, I joined the Blue Brain Project and the Human Brain Project in their quest to simulate the human brain. In my current position, I am part of ASML, the largest supplier in the world of photolithography systems for the semiconductor industry. Working at CERN confirmed my enthusiasm, ability, and preference for working in an interdisciplinary environment at the cutting edge of technology, and this I have certainly been able to leverage in my career.

Tao: Definitely a huge legacy! It was my 1st job, working with so many talents from different countries towards the same ambitious project. It is a pity that I could not go through the whole project. But I am following its progress and will definitely be happy to witness the success of HL-LHC.


Are there any skills or lessons that you learned here at CERN which are key in your current role in your new professional environment?

Liesbeth: I am a computational scientist, and the experience at CERN was a gift, in the sense that I was allowed to work and develop myself in the fields of mechanical and electrical engineering, which was a very broadening experience. In addition, I learnt how to operate and plan as a member of a multidisciplinary team. I had the chance to be part of many integration meetings where you would develop a better overall understanding of the Linac4 project. It gave me an improved understanding of project management, in the truly unique setting of CERN.

Tao: The skills I learnt at CERN greatly help my current tasks. Working at Google Fiber as a Hardware Engineer, we are targeting to make high-quality super-fast gigabit internet affordable and reachable to ordinary people around the world, which is another ambitious project. Similar to the projects I participated in at CERN, I am still designing the transmitting circuits and links. I am still benefiting from the experience at CERN. That’s why I think the LHC is not just a physics experiment. It is much bigger than we thought.

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