Riding a bike down the long tunnel from his loding to the control room of a synchronton in Osaka, Japan, was when the pay-off for all the difficult planning and work of PhD became clear to graduate student Nick Miller. He was workling with a team at facility on the other side of the globe. They were performing experimental techniques that had never been published. They were working with scores of some of the world’s best trained staff. They felt deeply connected to the scientific community.
A year ago Professors James Penner-Hahn and Roseanne Sension, Associate Research Scientist Aniruddha Deb, and graduate students Nicolas Miller (PhD Sension, 2019) and Lindsay Michocki (Kubarych Lab) all set forth for the Spring8 Angstrom Compact free electron Laser (SACLA) located halfway around the world near Osaka, Japan.
They had been planning this trip for months, having applied for “beam time” at the facility in February 2018. They were organizing details right up until their planes lifted off. The planning stage brought many surprising challenges, such as constructing a portable spectrometer to check on their sample’s purity after the international trip. The journey itself proved to be difficult with cancelled flights and a rather confusing train system.
Upon arrival, the group had to take on the further challenges of running an experiment at an unfamiliar, daunting place. Compared to American particle accelerators, the Japanese facility as more bureaucratic, says Miller. Badges are required to get into every part of the facility. The experiments themselves were grueling, as well. To get their data, the five-person team worked for five back-to-back, non-stop 12-hour shifts with two or three people at the controls at all times.
$100,00 an hour for SACLA operations
The difficult journey and long hours were in pursuit of data only attainable at SACLA. The facility is a wonder of modern engineering. It costs on the order of $100,000 per hour to operate. Particle accelerator facilities cost so much because they require many support staff. Particles accelerate down a kilometer-long tunnel filled equipment that rquires constant maintenance.
SACLA’s most impressive feature is its variable gap undulators. Miller describes these undulators as gigantic, wiggling magnets on motors. “They can literally be moved in synchronization. That allows you to tune the energy of the X-ray beam that is travelling through the tunnel.”
Making EXAFS possible
Maintaining such a complicated system requires many staff working together in congruity. When running in concert, the undulators make it possible to produce a vast spectrum of X-ray energies. Furthermore, SACLA is one of only three facilities that can produce light pulses as fast as 50 femtoseconds (50 quadrillionths of a second). An excited-state ultrafast EXAFS (extended x-ray absorption fine structure) experiment becomes possible with such a fast light pulse and broad spectrum. In an EXAFS experiment, researchers shoot a molecule with an array of X-rays. Calculations from the light wave’s interaction help researchers to create a picture of a molecule’s structure. Performing this experiment on a molecule in the excited state provides a picture of the molecule during a reaction rather than just before and after a reaction is finished. Obtaining this never-before-seen picture was what prompted the Penner-Hahn and Sension group’s venture.
More than just data
The trip also prompted realizations beyond exciting, new data, say the researchers. Planning experiments is life when you’re a PhD student, Miller points out. "All the hardships overcome for this trip reminds us how incredible it is to work in the chemistry department at University of Michigan with the resources and connections to perform state-of-the-art experiments," adds Miller who completed his PhD in 2019. "A more transcendent truth about our work is the brilliant realization that science connects us with each other and that makes the challenge of a chemistry PhD something worth pursuing."