Where are they now? 
 -- An Interview with KIPAC alum Aurelien Bouvier

Jun 22, 2015

In the series, "Where are they now?" we check in with KIPAC alumni: where they are now, how they've fared since their days exploring particle astrophysics and cosmology at the Institute, and how their KIPAC experiences have shaped their journeys.

Next up is Aurelien Bouvier, a KIPAC graduate student from 2005 to 2010, whose time at KIPAC working on the Fermi Gamma-ray Space Telescope (Fermi) and the Cherenkov Telescope Array (CTA) sent his life in a totally different direction from where he had thought he was initially headed.

LW: Tell us all little bit about yourself and your academic background. I understand you're from someplace a little out of the ordinary?

AB: I grew up in New Caledonia, which is a French special collectivity in the southwest Pacific near Australia, from when I was nine until the end of high school. My parents are huge travelers and when my dad got an offer to be the new nephrologist in New Caledonia, he jumped on it. I didn't have a say in the decision but I loved it. For undergrad, I moved to France where I graduated from Ecole Polytechnique in 2005 with a major in Physics.

As a kid, my dream was to become an astronaut but my interest in physics rather than Engineering naturally geared me for astrophysics instead. In 2005, after a four-month internship at the Subaru Telescope in Hawaii, I started grad school in the Physics department at Stanford.

LW: What projects did you work on while you were at KIPAC?

AB: During my PhD years I worked on the GLAST/Fermi project. [Fermi was originally named the Gamma-ray Large Area Space Telescope, or GLAST.] My official advisor was [Emeritus] Professor Tuneyoshi Kamae, although in practice my supervisor was Hiroyasu Tajima, who is now a professor at Nagoya University in Japan. My thesis focused on gamma-ray bursts and the extragalactic background light.

It was a very exciting time to join Fermi (about two years before the launch of the instrument), which was thrilling and stressful at the same time. My PhD was hanging in the balance after all! Looking at the very first data pouring out of the instrument was incredibly exciting for me and gave me a sense of slowly becoming a part of the scientific community. I'll always remember coming to Hiro's office holding in my hands what I was convinced was the first detection of a gamma-ray burst by Fermi.

And whenever I'd go in Hiro's office he always had pieces of hardware. I'd always end up asking how something worked while talking to him.

LW: Had you done much with hardware before?

AB: No. When I started grad school I wanted to be a theorist using just chalk and a blackboard. The science there was a lot of fun — but I developed a very strong interest for instrumentation during my PhD. At SLAC all the hardware people were there—any conversation immediately got deeply into the details of how something worked. By the time I left I realized I wanted to be surrounded by cables and blinking lights.

Fermi is such a beautifully designed detector. I yearned to be part of a team that built amazing hardware. This is why I went to UC Santa Cruz for my postdoc.

LW: What did you do during your postdoc?

AB: I worked in David William's group on instruments for the Very Energetic Radiation Imaging Telescope Array System and the Cherenkov Telescope Array, both of which are focused on a ground-based approach to detecting very high-energy gamma-rays, as opposed to Fermi, which is space-based. For this technique, an array of telescopes is deployed on the ground to image the shower of particles that a high energy gamma ray creates when it enters the atmosphere [previously discussed in this KIPAC blogpost.]


Above: Left - VERITAS PMT's worked on by Aurelien, and on the Right - The new miniaturized and more sensitive silicon photodetectors designed for CTA that replace the PMT's.  The diamater of the pixels on the left is about 2.5cm, and the size of the individual ones in the 4x4 array on the right is about 0.5 x 0.5 cm. (Images courtesy Aurelien Bouvier.)

At UCSC, my work became very hardware-oriented. We had a photonics lab which focused on photodetector characterization. I spent a lot of time in the lab, surrounded by cables, soldering irons and an occasional burning smell. It was amazing training to develop hardware skills. In science experiments, much of the hardware is very custom. It's very hard to find off-the-shelf components that will do what you want. And when things are constantly broken you have to learn how to fix them.

The most fun and satisfying part of my postdoc years was being part of a team that designed a new type of telescope never built before called a Schwarzschild-Couder telescope. In particular, the characterization and simulation work we did to explore the use of silicon photomultipliers (a semiconductor-based detector) for future very high-energy gamma-ray instruments like the Cherenkov Telescope Array was very fulfilling. I became convinced that I wanted to dedicate myself to building "cool" hardware. Silicon Valley was just next door and a paradise for engineers so I simply took advantage of it.

LW: So you're not at a software company?

AB: No. I'm at InVisage Technologies. I joined at the end of 2013, and it felt like a natural transition to me. InVisage kept me in the field of building semiconductor cameras. At UCSC, the cameras were used to look at the night sky while at InVisage we're working to put them in smartphones but the underlying physics is very similar. One interesting difference is that InVisage is a fabless semiconductor startup that is building the very first image sensor based on quantum dot materials instead of silicon, which is overwhelmingly used today in digital cameras.

It's been a great experience so far. I was hired as a characterization engineer, but once I got inside and learned about it—that's the good thing about startups. If you're motivated, you can do whatever you want.

What I like about the startup environment is the very high visibility and impact that your work can have. There is a strong sense of being part of a team working toward a common goal. And if you are motivated you can learn a ton just because there is this constant need to work in areas where we do not have any real experts at hand.

I was a bit nervous at first that I might not have what it takes to get adjusted to this new world but in the end a lot of the skills I learned in academia apply directly to the industry. I was trained as a scientist, specifically a physicist, but on a day to day basis my life is not that different. I look at data, do scientific reasoning to try to determine why something isn't working, come up with experiments to see if I'm right.

Oh and we actually hired 2 more astrophysicists since I joined so the astrophysics breed is doing quite well here. (Laughs.)

Above: A cross section of a QuantumFilm pixel array. Light passes through the color filter array and is detected by the quantum dots in the QuantumFilm layer. The higher positioning of the photosensitive layer allows the QuantumFilm pixel to detect more photons, store more electrons, and reproduce colors more accurately—all with a thinner camera module. (Image courtesy InVisage Technologies.)

LW: How does working at a startup differ from academia?

AB: The pressure and pace can be quite intense at times so it's definitely not for everybody. In academia there's a certain freedom to explore an idea to its fullest. People give you time. In business your time is driven by what's determined to be the highest priority and you can make a case for what you like but you might not have a say.

LW: What do you miss the most about KIPAC? About academic settings?

AB: KIPAC is an incredible environment to do science surrounded by passionate and smart people. I feel lucky to have been part of it for a little while. A lot of the analysis skills I learned there I still use on a regular basis.

What I miss most about academia is that the large majority of people there are truly passionate about what they do and the environment favors easy communication and exchange of ideas. Talks and colloquia are great of course but also don't be afraid to knock on someone's door to ask questions—even stupid ones—or discuss something that intrigues you.

That's what I try to do when I'm surrounded by smart people: I suck their blood. Intellectually speaking, of course. (Laughs.)