In a series of portraits, SOLEIL goes out to meet those who make the synchrotron what it is. For this third episode, Jean Susini, SOLEIL's new Director General, agreed to take part. In an interview, he reflects on his career choices—guided, by his own admission, by a bit of chance and a lot of curiosity—as well as the challenges of the SOLEIL II renewal project.
As of September 1, 2024, Jean Susini is SOLEIL’s Director General, having dedicated his entire career to cutting-edge research infrastructures like synchrotrons. A career path "far from obvious," says the scientist, who once considered becoming a carpenter. "But in over 35 years on the job, I’ve always been very happy wherever I was, and today, that hasn’t changed," says Jean Susini. "Plus, to work on a synchrotron, you need to have a tinkerer’s soul and enjoy working as part of a team," he adds with a smile.
Beginnings with the pioneers
Originally from Savigny-sur-Orge in the Paris region, Jean Susini earned his PhD in physical chemistry from Pierre and Marie Curie University (now Sorbonne University) in 1989. Although he’s always loved hands-on experiments, sometimes to his own peril—he admits to endangering the family home as a child by mixing chemicals—he also recalls being "moderately motivated" by school, and his academic path didn’t exactly suggest long studies. "If someone had told teenage me that I’d be doing a PhD, I’d have been skeptical," he says. "But things changed when I had more freedom at university, and I was lucky to meet the right people at the right time."
During his master’s program, he met pioneering scientist Yvette Cauchois, who was the first in Europe to conduct X-ray spectroscopy experiments using synchrotron radiation—first at the National Laboratory of Frascati, near Rome, in 1963, and then at the LURE (Laboratory for the Use of Electromagnetic Radiation) in the early 1970s, thanks to the installation of a beamline on the Orsay Colliding Ring (ACO), which is now a museum.
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Collisions vs. Radiation: 2 different uses for synchrotrons Initially, this light was considered an unwanted byproduct because the lost energy reduced particle acceleration. But researchers, including Yvette Cauchois, quickly realized that this radiation was highly directional—like a laser—and incredibly powerful, up to 10,000 times brighter than sunlight, with a broad wavelength spectrum ranging from X-rays to infrared. Source : cea.fr |
From Paris to Grenoble
Advised by Yvette Cauchois, Jean Susini pursued his PhD at the CEA in Bruyères-le-Châtel, the Physical Chemistry Laboratory in Paris, and LURE, focusing on X-ray optics. Meanwhile, he learned about the ESRF project, a new European synchrotron facility in Grenoble. Just one year after 11 European countries signed the ESRF’s founding statutes and before construction even began, Jean Susini joined the project in April 1989, right after completing his thesis.
Moving from the Paris metropolitan area—where French was the dominant language—to the mountains of Grenoble, Jean Susini found himself working in an international team that communicated exclusively in English. "I wanted above all to step out of my comfort zone, and I was very curious," he explains.
What started as a five-year stint at ESRF turned into a 32-year career, spanning multiple roles and giving him a comprehensive understanding of synchrotrons: science, administrative leadership, construction, renewal... "I was incredibly lucky to witness the birth of such a major facility. At the time, it was the largest synchrotron in the world. Working at ESRF for so long was an immense privilege." Initially part of the optics group, Jean Susini led the design, construction, and operation of the ID21 X-ray microscopy beamline starting in 1994: "my first major project." By 2000, his responsibilities expanded to include the development of a hard X-ray microprobe on ID22, his "adopted beamline," as well as an infrared microscopy station. Although these instruments were intended primarily for biology, they ultimately contributed to the fields of environmental and heritage science—areas in which Jean Susini became heavily involved.
A facilitator’s role
In 2009, Jean Susini was appointed Director of a new division at ESRF: the Instrumentation Services and Development Division. "Designed as part of the synchrotron's renewal, it pooled human and technical resources to support the beamlines and accelerators while also creating critical mass for innovative instrumentation projects," he explains. "The division, built mainly through internal mobility, brought together 130 people working on mechanical design, detectors and electronics, X-ray optics, beamline control, and data analysis. It played a key role in completing the two phases of ESRF’s renewal, both in terms of human resources management and project leadership, working hand in hand with the Machine and Experiments divisions."
"I was eager to come to SOLEIL, particularly to help strengthen its position within the unique and rapidly expanding Paris-Saclay ecosystem."
After leading the division for more than six years, Jean Susini was appointed Scientific Director of Life Sciences. His primary missions? Ensure all beamlines were operational, inspire a scientific direction under ESRF-EBS (the synchrotron modernization phase), and strengthen relations with the user communities. "I was a facilitator, and the human dimension was very important to me," he recalls. He held this position until 2021. "After three decades at ESRF, I felt I had reached the end of a cycle and a great adventure," he says. "I had SOLEIL in the back of my mind, but until then, I hadn’t seriously considered joining the synchrotron." One day, by chance, he learned that a position was open and decided to apply. "ESRF is a structure supported by over twenty countries, and its international nature made regional synergy more complex," he explains. "I was eager to come to SOLEIL, particularly to help solidify its place in the unique and expanding Paris-Saclay ecosystem," he adds. "Plus, I wanted to use the experience I had gained to benefit the French synchrotron."
A new challenge
Initially recruited as SOLEIL’s Scientific Director for Life Sciences, Jean Susini encountered "welcoming, competent teams, with outstanding research being carried out, both in the Experiments division and in the Accelerator and Engineering division." He was pleased to be given "enough latitude and trust to bring [his] own management style."
In September 2023, Jean Daillant, SOLEIL’s Director General since 2011, announced his departure to lead ESRF. After careful consideration, Jean Susini decided to apply for his position, once again stepping out of his comfort zone, and offering his vision for SOLEIL’s evolution towards SOLEIL II.
"SOLEIL is the result of the efforts of a previous generation; mine is just as responsible for what we will pass on to future generations."
On December 22, 2023, it became official: SOLEIL’s Board of Directors appointed Jean Susini as Director General of the synchrotron, a role he assumed on September 1, 2024. Among his top priorities is leading the first phase of SOLEIL II. "It’s a major challenge, as it involves not just technical modernization but also changes in work methods and internal organization," he explains. "With SOLEIL’s renewal, we’re transitioning from two decades of operations—a significant period but a more linear one that was easier to plan—to a phase particularly ripe for change," he adds. "My mission is to accompany this necessary evolution, especially by finding strong internal partners and providing collective solutions to the inevitable technical problems, economic fluctuations, and unforeseen challenges that will arise."
However, Jean Susini is quick to put his role into a broader context: "SOLEIL is the result of immense efforts from previous generations, and my generation is equally responsible for what we pass on to future generations," he says. "The synchrotron is, above all, a collective adventure—for passing on knowledge, but also, more pragmatically, for passing on a modern, pleasant place to work." A builder’s spirit? "Maybe," he concedes.
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SOLEIL II, a more efficient synchrotron Twenty years after SOLEIL’s creation, both science and the role of this research infrastructure have significantly evolved. SOLEIL must adapt to the new fields of investigation that have emerged in recent years. Over the course of five years, construction and digital transformation will take place to renew research instruments and access methods. This renewal will allow experiments to be up to 10,000 times faster and 1,000 times more sensitive, with much more precise nanometric resolution, as well as energy savings. |
Brick by brick
Faced with the magnitude of the upcoming projects, does Jean Susini feel any apprehension? "For the first time, I will be confronted with the stress of the final decision, in the sense that I am the legal head of SOLEIL," he admits. "Fortunately, I am supported by a team of experts who know how to make choices in their areas of expertise," he adds. "As I mentioned earlier, SOLEIL can rely on a very good working atmosphere, excellent scientific and technical standards, as well as motivated staff to advance research," Jean Susini continues.
"To be a manager, in research or elsewhere, it is essential to be attentive to human nature and to love it in all its variety."
When asked about the most important qualities for working in research and particularly in a leadership role, his first response takes him back to the memory of another path he almost followed. During his university years, Jean Susini worked for six years as a youth counselor alongside his studies, caring for groups of children aged 12 to 17 in a leisure center. "I loved that job," he recalls. So much so that he took a training course and considered changing careers. "That experience taught me the basics of management," he explains. "To be a manager, in research or elsewhere, it is essential to be attentive to human nature and to love it in all its variety. It's impossible to fully grasp, and that’s a good thing!" he believes. "In any professional or social group, I am convinced that the key is to assert yourself."
What else is just as important? "Patience and curiosity," he says. "Because science is built brick by brick, and especially collectively," he continues. Is this a reference to one of his favorite films, The Wall by Pink Floyd, or a hint of a former interest in craftsmanship? "Oh no, it's mostly how I conceive my professional life, but also a piece of advice I would give to anyone wishing to embark on research," he concludes.
Jean Susini’s mini biography
1989: PhD in physical chemistry, Université Pierre et Marie Curie (now Sorbonne University), Paris, France
1989 - 1994: Researcher in the optics group, ESRF, Grenoble, France
1994 - 2001: Principal scientist for beamline ID21, ESRF
2001 - 2009: Principal scientist for beamlines ID21 and ID22, and deputy head of the X-ray imaging group, ESRF
2009 - 2014: Head of instrumentation services and development division, ESRF
2015 - 2021: Life Sciences scientific director, ESRF
2021 - August 2024: Life Sciences scientific director, Synchrotron SOLEIL, Saint-Aubin, France
Since September 1, 2024: Director General, Synchrotron SOLEIL
On Linkedin
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Jean Susini's film picks
While he admits to having no "overwhelming" passion, Jean Susini's curiosity has led him in many directions: cooking – "I maybe enjoy making desserts a little too much," DIY, reading – "especially newspapers," playing checkers – "I play every day, it has taught me anticipation," and also cinema: "I love the big screen, I have very eclectic tastes and can easily watch a film 10 times if I like it." The list of his favorites that he’s seen at least ten times "would be far too long," but he mentions a few at random:
The Wall - 1982, by Adrian Parker, based on the concept album by Pink Floyd
"When it came out, I went to see it 7 times... in 7 days! It was shown at Kinopanorama, a huge cinema in the 15th arrondissement, which closed more than twenty years ago. This is an essential film for me, more for its visual interpretation of an album that deeply affected me than for its message."
Excalibur - 1981, by John Boorman
"A masterpiece of medieval cinema recounting Arthurian legends. Boorman's film offers an aesthetic, bloody, and raw vision of the Round Table, with its dramas, plots, and deviations. A classic on the subject, just like Monty Python and the Holy Grail, though in a very different style, of course..."
Parasite - 2019, by Bong Joon-ho
"In the form of a fable-thriller-comedy with class struggle undertones, this film is highly transgressive and presents a fascinating and original progression, with masterful direction."
Anatomy of a Fall - 2023, by Justine Triet
"An outstanding work with incredibly controlled direction! Under the guise of a conventional 'courtroom drama', Justine Triet – as usual – methodically explores the human soul."