Department of Energy

10 Questions for a Physicist: Uwe Bergmann

June 23, 2011

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Uwe Bergmann  | Photo Courtesy of Brad Plummer, SLAC

Uwe Bergmann | Photo Courtesy of Brad Plummer, SLAC

While officially billed as a physicist at SLAC National Accelerator Laboratory, our latest 10 Questions guest may be more aptly titled a scientific detective. In this fascinating addition to 10 Questions you’ll learn about how he used x-ray techniques to uncover historical mysteries from fossilized dinosaur remains to ancient mathematical texts. 

Question: Why did you decide to pursue a career in science?

Uwe Bergmann: I didn’t plan to do it. That’s the true answer. I started with physics. I had some friends in school and we thought it would be cool to study physics and somehow that stuck with me. None of my friends stayed in physics.

Q: What brought you to SLAC?

UB: The short answer is x-rays and water. Already at a young age I wanted to move to faraway places close to the sea, and from where I grew up the farthest big city in Germany was Hamburg. That’s where I got my Diplom (similar to a Masters) and my first taste of x-rays. I then moved across the Atlantic to Long Island doing my Ph.D. work at Stony Brook University and Brookhaven National Lab working at the National Synchrotron Light Source, the largest x-ray facility at the time. 
After a two year postdoc at the European Synchrotron Radiation Facility in Grenoble, France, I moved to Lawrence Berkeley National Lab where I worked for seven years, developing and applying new x-ray spectroscopy techniques. In 2003, there was an opportunity for some research on water which I couldn’t do there and a very good friend and colleague of mine encouraged me to apply at SLAC. I started at SLAC working for several years at the Stanford Synchrotron Radiation Lightsource, and two years ago there was this incredible opportunity to move to the Linac Coherent Light Source (LCLS), the world’s first free electron x-ray laser. LCLS produces ultra-short ultra-intense x-ray pulses -- a billion times brighter than those produced in synchrotrons -- that we think will revolutionize how we will understand the atomic and nano world. It’s one of the most exciting places in science you can be right now, and I would have never dreamed to be here.
Q: What projects are you working on right now?
UB: We’re working with a large collaboration from around the world on a study of how exactly the tiny machines that are in plants and algae use sunlight to split water to oxygen in photosynthesis. Our goal is to eventually make an atomic resolution movie of the process, and we are going to need LCLS to do that. If we could find the answer to this question we might learn how to better use sunlight to create new fuels. 
In a very different research field I’m working with a group mainly from Manchester, England, on x-ray imaging of fossils. We are trying to find out what is left from the original animal chemistry after over 100 million years, and x-rays are the most sensitive probe to do that. This is quite different from my other research, but equally fascinating. I guess I have always been a very curious person and x-rays are just such a powerful tool to quench this thirst. 
Q: Do you have advice for students who may be interested in science careers?
UB: Yes, I think science is one of the few jobs which just gets better over time, it never gets more routine. You do need to be tenacious early on, but you will be rewarded a hundred times over. And you often don’t know where it leads you to, except that it will be exciting.
Physicist Uwe Bergmann, above right, says that new, powerful x-ray lasers will be able to make "ultra fast movies of the atomic world." | Courtesy of: SLAC National Accelerator Laboratory
Q: What can x-rays do to improve our understanding of the world?
UB:  I think x-rays are incredibly versatile as a tool because on the one hand they allow you to see through things and on the other hand they allow you to look at extremely small things like the size of atoms and molecules. And while both are almost independent of each other, they are very important qualities. For example, most people know what impact x-rays have had on medical imaging, but in more scientific applications x-rays have been used to view the structure of thousands of different molecules in biology as well as many other research fields. With the ever more powerful new x-ray lasers, like LCLS, we will be able to push these limits from still images to ultra fast movies of the atomic world. This will have impacts in medicine and lead to more efficient ways to use our energy resources. The best is yet to come.      
Q: You mentioned your work with fossil imaging earlier. Can you share a bit about your experience with a half-dinosaur/half-bird fossil? 
UB: We were lucky to work on one of the most iconic fossils, Archaeopteryx, the 150-million-year-old ancestor of modern birds. The first Archaeopteryx fossil was originally found shortly after Darwin published On the Origins of Species. It is one of those pivotal transitional fossils with a creature that has anatomic features of a dinosaur, but also has modern bird feathers and could probably fly. So we were lucky -- extremely lucky -- to be able to get one of the best preserved fossils of all the eleven which exist of this animal. And we found that when using a technique called x-ray fluorescence imaging we were able to see that remnants of the original feathers of the bird are still preserved in the fossil. Although you can see the imprints of feathers, no one thought there was anything actually left of the original feather material. But we found it through x-rays. 
Q: You’ve also used x-rays to read ancient texts. What did you find?
UB: I was at a conference on photosynthesis in Germany and stopped by my parents' house before flying back to the U.S. My mom gave me a popular magazine (GEO, similar to National Geographic) which had an article about the Archimedes Palimpsest -- the oldest surviving copy of work by Archimedes.  
Several pages in the book were indecipherable; the original text had been rubbed off the parchment and was covered in paint and other writings. Scientists had been trying to view the text for several years, using all different types of optical imaging techniques.  When I learned that the original text was written with an iron based ink, I thought that we should be able to use x-ray fluorescence from a synchrotron. We knew that this technique could detect even tiny amounts of iron and the idea was to scan the pages for iron particles left from the original ink, even if they were covered. 
What had been invisible for centuries was made, right before our eyes, visible.  Line by line, Archimedes' original writings began to come to life, literally glowing on our screens.  It was the most amazing thing.  This same technique is what we're using now for our fossil imaging.  Our technique, our ability to rapidly scan entire pages, entire fossils, it's very, very exciting.  And promising for a variety of studies.
Q: What do you enjoy doing outside of the lab?
UB: I like the outdoors and I spend as much time as I can outside.  I like to swim, I like to go to the ocean. Golf, running, skiing, biking -- I bike to work every day. When you do the kind of work we do, I think that’s the best complement you can have -- to do something for your body as well. 
Q: What is your favorite gadget in the lab?
UB: Hm, I like the water dispenser where you get the filtered water. I use it every day. 
Q: Last question: what is on your reading list right now?
UB: First of all, I’m a slow reader, partially because I always fall asleep. I finished the Millennium Trilogy and I just started a book called The Divinity of Doubt. It’s from Vincent Bugliosi, best known for prosecuting Charles Manson. It’s about the God question. The human relation to that question fascinates me. I have read many books on it and, as a scientist, to find a lawyer’s perspective on this topic is very refreshing.
Niketa Kumar is a Public Affairs Specialist in the Office of Public Affairs.