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How did Master student Elze Knol experience her internship at IMM?

‘Developing equipment goes hand in hand with fundamental material research’

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Elze Knol is Master’s student in Physics and Astronomy. As part of her specialisation 'Physics of Molecules and Materials' she is doing an internship at the department of Scanning Probe Microscopy of prof. Khajetoorians. Here, scientists develop and use scanning probe microscopes (SPM’s) to study materials up to the atomic scale.
Knol is a returning student. During her Bachelor's she was intern at the same department and got involved in the setup of a new SPM in the Nanolab, which houses many of the microscopes of the Institute for Molecules and Materials. SPM’s probe materials by scanning the surface with an ultra-thin needle. The images are used to study behaviour and interactions up to the atomic scale, often at extremely low temperatures and in vacuum.

Improving microscopes

During her first internship, Knol designed a supporting frame, part of the vacuum chamber and shields that deflect heat radiation. With little designing experience, Knol got help from the people at the department and technical experts of the TechnoCentrum of Radboud University. ‘Many people were thinking along’, she says. ‘I learned about designing and how to find good arguments for important decisions. Normally, design is not a big part of the Bachelor’s programme, it is nice I got this experience.’|

But why design your own machine, when you can also order a SPM ‘off the shelve’? Knol explains that if you want to distinguish yourself in research, you need to improve existing machines. Especially to make them operate at very low temperatures. ‘At our department there are four setups’, she says. ‘With liquid helium, two of them can be cooled to minus 269 degrees Celsius. The other setups can go even colder. We can cool samples to only 30 millikelvin, a fraction above absolute zero. There are not many SPM’s in the world that can do that.’

Physicists hope to learn more about material properties like superconductivity, which only exist at low temperatures. Also, magnetic properties of single atoms can be investigated. In general, the resolution of SPM gets better at lower temperatures.

To test the SPM Knol measured graphite, the material you can find in pencil points. Part of the hexagonal atomic structure of the material can be seen. Credit: dr. Henning von AllwördenAs a physicist, Knol worked together with the chemists that use the same laboratory. ‘Every two weeks we have group meetings’, she says. ‘Although chemists use techniques like SPM, they focus on different topics and questions. For example, they want to know how molecules like polymers look like on a surface and how they react with other molecules. Unlike many physicists, they don’t work in vacuum or at extremely low temperatures. Sometimes they apply SPM to liquids. The interaction between chemists and physicists is interesting. We can learn from each other.’

Flexibility

One of the best things of the internship was the atmosphere in the research group, according to Knol. She could easily approach colleagues for questions. Also, she liked the supervising style of prof. Khajetoorians. ‘He is honest, if he doesn’t like the work he sees, he will let you know’, Knol says. ‘On the other hand, he can get real enthusiastic from good work. This really motivated me.’

Knol combined her internship with other work. She followed Bachelor’s courses, she did commission work at the student swimming association, and had a small job. ‘Sometimes it was difficult to combine everything’, she says. ‘I managed because of the flexible working times at the department. This was possible because of the type of work I did. When you are directly involved in measurements, I don’t think you can let colleagues wait very long.’

Superconductivity

Nanolab 4k_omicronIn her Master’s internship, Knol will work on the most advanced SPM in the lab, one that cools samples to 30 millikelvin. ‘After extensive testing it is now ready to be used by researchers, but there are still things to be fine-tuned’, she says. ‘For example the cooling settings. How fast the helium must flow to reach the lowest temperature.’

At the same time she will do experiments. To examine properties of aluminium, which starts to superconduct at temperatures less than a degree above absolute zero. ‘For optimising the setup you need to test samples. Developing equipment goes hand in hand with fundamental material research’, Knol says.