Peter Tiemeijer received an M.Sc. degree in experimental physics and M.Sc. and Ph.D. degrees in theoretical physics from the University of Utrecht, The Netherlands. His Ph.D. work was on numerical analysis of the relativistic dynamics of quarks in mesons. After that in 1994, he joined Philips in Eindhoven, The Netherlands, to develop new hardware for electron optics. He worked on electron monochromators, new field-emission sources, aberration correctors, energy filters, and he designed the optics of the Titan electron microscope. During this period, Philips’ activities in electron microscopy were taken over by FEI Company, which was later taken over by Thermo Fisher Scientific. He has about 35 scientific papers and 25 patents.
What is your specific area of research? How would you explain it to young children?
⬤ My colleagues and I work on making our electron microscopes better, to enable the users of our microscopes to get better understanding of the composition and atomic structure of their samples. My specific area of work is the optics of the microscopes, so I mainly work on the electric and magnetic fields (‘the lenses’) that guide and focus the electron beam to the sample and further to the cameras and detectors.
Why did you choose your research field? Were you inspired by someone?
⬤ When I was young we knew that atoms exist but we could not see them because they were too small. But nowadays microscopes are so powerful that we can simply see these atoms. To me, this moved atoms from the realm of theory to that of reality. Coming from a time where atoms were invisible, I find it wonderful and inspiring to see them sitting around each time I am at the microscope.
How does your life as a top scientist compare with your expectations of it when you enrolled in Physics?
⬤ When I started in physics I enjoyed using the equations of physics to calculate how things would move or behave, and that was what I wanted to do as a scientist: to think about something new (for example, a robot or a computer or a theoretical model about sub-atomic particles), to calculate how it should behave, and then to build it and test it, and be happy when reality and calculations agree. This still applies to my present work. We have the same joy when some new part of our microscope works according to design and calculations.
What traits might a child possess that may indicate an interest or aptitude for your research field?
⬤ When you like building things, calculate their behavior, control them with computers, and when it is ok for you that it may take months or years before everything is ready and fits together, then you are surely apt for this field.
What are you currently working on and what is your long-term research goal?
⬤ When I started in this field, images from an electron microscope were mostly black-and-white: smaller white dots for lighter atoms and bigger white dots for heavier atoms. Since then, various kinds of spectroscopy have been introduced that can ‘color’ these images. Then color represents (for example) the type of atom. My long-term goal is to make these techniques so reliable and so simple that any user can use them and wants to use them.
Why is your research important?
⬤ Our electron microscopes help scientists and companies to understand their samples at the atomic level. This helps them developing, for example, new medicines, better materials (e.g. better batteries, better solar cells, stronger and lighter composites), better catalysts, or faster and more powerful computer chips.
Would you like to mention one or more of your most important scientific findings?
⬤ My first project was to design and build a monochromator for the electron microscope. I worked on this for six years. This monochromator reduces the energy spread in the beam by a factor of ten. It was introduced 20 years ago. It can improve the resolution to as good as 0.5Å (about half the diameter of the smallest atom), the best in the world. About 90% of the transmission electron microscopes in the world that have a monochromator, have a monochromator of my design.
What is it that you like to do when you aren’t working on research?
⬤ Reading, singing, hiking.
Are there gender differences in your research environment and what are current opportunities and challenges for women in science?
⬤ I think that there is a general impression that, when you are working in technology and certainly in physics, you are most of the time ‘working with things’, not with people. This impression is wrong. Technology and science are group activities: I meet and work together with colleagues or customers, together we discuss or design instruments and methods, together we do experiments; it is not often that I sit just by myself in my office. Nevertheless, this false impression of ‘not working with people’ is something that got stuck to physics and it often makes you feel you have to defend why you choose to work in physics. I think that especially women, when they enter physics and science, have to confront this false idea that they are ‘not going to work with people’.
Now for the big picture: what is your assessment of the current state of your area of research? (i.e. where do you see it going, what expectations for the future, etc.)
⬤ In the field of traditional imaging, electron optics does not hold many secrets for us anymore: we know how to make 0.5Å resolution and we know what steps we can do if we want to improve on this. In this field most scientific advances will probably happen in the area of applications. For example, in cryo-electron microscopy, advances in sample preparation, in cameras, and in software reconstruction techniques gave such progress that biologists can nowadays make 3D reconstructions of their specimens (such as enzymes or viruses) so sharp that they can see where all the individual atoms are. This is something that not many people would have thought possible ten years ago, given that biological specimens are extremely quickly damaged when you look at them with an electron beam. In this traditional field, we are working on making the microscopes more reliable, easier to use, and more automated. Outside this traditional field, I see interesting developments happening in the way how we probe the specimen. For example, our knowledge of the exact mechanism behind the damage that the electron beam causes in beam-sensitive materials is limited but quickly increasing. Maybe, with a good understanding, we can find ways to adjust the illumination so that we can manipulate how the energy deposited by the beam in the sample is dissipated, and then tune it in such a way that the damage to the sample is significantly reduced. Another good example is the present Q-Sort project, in which we exploit the quantum wave property of electrons that a single electron can probe one aspect of a specimen (such as a rotational symmetry) not at single position but simultaneously over a whole region.