Structure and order define our understanding the universe, from the macro to the molecular scale. However, understanding the structure of molecules is hard, because they are small. Like, really, really small. A popular way to investigate this for nearly 100 years has been X-ray crystallography – crystallizing your molecule or material of interest into an ordered array, bouncing X-rays off them to collect the diffraction pattern (how the X-rays are scattered/reflected by the molecule) and figuring out the molecular structure from that info. Since many materials can form crystals (including salts, metals, minerals, semiconductors, and various inorganic, organic and biological molecules like proteins and DNA), X-ray crystallography has been key to a century of advancements in a range of scientific fields, from atomic physics and physical chemistry to biochemistry and molecular biology.
As a general rule, the more powerful your X-ray source, the more diffraction events you can create and measure, and the more accurate your structural determinations can be. This has resulted in a role for synchrotrons, originally developed for high-energy atom-smashing physics experiments, in these sorts of experiments. Our next curator, Dr Christine Beavers (@XtalGrrl) of the Advanced Light Source Facility, Lawrence Berkeley National Laboratory, enables researchers to use synchrotron beamlines to do exactly that. We fired questions at her and she diffracted them in the following pattern:
How did you end up in science?
Always been interested in how things work, and especially at an atomic level, so chemistry was a natural fit for me. I was born in Oakland, California. I am a California native, and I can see (on a good day) the hospital where I was born from where I work. I did both my B.S.(Chemistry) and Ph.D (Analytical Chemistry)at the University of California, Davis. In grad school, I thought I was going to become a mass spectroscopist, but then I learned about crystallography.
How did you end up in crystallography, and what is it about the beamline that makes it better than traditional sources?
UC Davis is home to one of the most well known crystallographers, Marilyn Olmstead. She saw my aptitude with spatial explorations and took me on as a grad student. She gave me the latitude to explore using a syncrotron for crystallography. At Davis, I did a lot work with the lab X-ray tube, which is a tungsten cathode, which emits electrons towards a target anode (usually molybdenum or copper) accross a high voltage. These electrons slam into the target material, and cause the emission of X-rays at characteristic frequencies. This process isn’t hugely efficient- you produce a respectable amount of the characteristic X-rays, but you also produce a lot of other frequencies of X-rays, called bremsstrahlung, which you have to block or filter out. Using a beamline, you are receiving the X-rays directly from the radial deceleration of the electrons in the storage ring of the synchrotron. You can choose whatever frequency (or energy or wavelength, as we usually think of X-rays), because the synchrotron can produce a continuum of X-rays. Not to mention that the X-rays from the synchrotron are much more intense (more photons) and much more brilliant (highly linear) than any lab source.
What is your research about?
I am a bit of a research butterfly. My specific job calling is to support beamline users to do their science, hopefully using single crystal diffraction. Whatever they come with, I get to help them. The majority of the users I interact with work in mineral physics, like Abby Kavner, who are expanding our knowledge of the deep earth, by doing high pressure and high temperature work. I am also currently involved with numerous groups who are trying to do “high” pressure work on chemical compounds, which are much softer but sometimes really fascinating. My personal research goals are to improve the success of high pressure explorations- can we get better data? Can we determine the 3-D structure in more cases with less data?
What do you like to do when not in the lab?
I ride my horse. I have been riding horses since I did a riding camp in Girl Scouts when I was 10, and I haven’t been able to quit since. A major motivator for me to get educated and get a well-paying and satisfying career was to support my horse habit, but then I went into science! Satisfying, yes! Well-paying, well…not bad. My horse is a mare named Kierra, and I am just about to go out and have my weekly lesson from my trainer right now!