Coincidentally, following my post “Talking About Smart Women,” I was recruited to write an article for the MRS Bulletin about the recent invention of this year’s L’Oreal-UNESCO laureate from Europe. Of course, I jumped at the opportunity.
Prof. Pratibha Gai from the University of York won the Women in Science award for her development of the Environmental Transmission Electron Microscope (E-TEM). The original Transmission Electron Microscope (TEM) was designed in the 1930’s by Max Knoll and Ernst Ruska, and Ruska later won a Nobel prize for it’s invention.* This microscopy technique allows the operator to view single atoms, features a quarter of a nanometer in size (or 10,000,000,000th of a meter). The instrument is capable of this fine resolution because instead of using light as the probe like a classical microscope, it uses electrons. This is necessary since the wavelength of the probe must be smaller than the the object being investigated: since electrons are fractions of the size of atoms (remember electrons are part of atoms), atomic-scale features can be observed. Light has a wavelength of about 400 nanometers, so it is incapable of focusing in on atoms.
The problem with a normal TEM is that it requires the sample to be at cryogenic temperatures (think liquid nitrogen and Terminator) and in ultra high vacuum (essentially the vacuum of space). These conditions are required to freeze out any molecular motion and to ensure sample cleanliness (you can’t have a dirty sample if there is no atmosphere!). The problem is that, if you want to study a chemical reaction, you need to be at real-life, ambient conditions.
This is where Prof. Gai comes in. Her E-TEM is capable of imaging single atoms under “environmental” (ambient) conditions, which she achieved by creating a tiny area above the sample where gas is controllably flowed. This modification was very difficult because the sample still needs be accessed by the electrons, which are dissipated by gas. The design has now been commercialized and is being used world-wide.
Not only did Prof. Gai develop an amazing new scientific tool, but she is very positive about the role of women in science. She met me for the first time as I interviewed her, but when she found out I am also a scientist, she encouraged me to stay in the field. She noted that since women make up half of the population, it is important that they make up half of the scientists too.
You can find my article about Prof. Gai and her newest E-TEM work here.
*Ruska actually shared the prize with Binnig and Rohrer for their invention of the scanning tunneling microscope, the instrument I work on.