Portrait Annette Pietzsch: Researching fundamental phenomena of our world

Annette Pietzsch infront of her instrument at the PTB hall at BESSY II.

Annette Pietzsch infront of her instrument at the PTB hall at BESSY II. © HZB / M. Setzpfandt

The green arm of the new METRIX instrument, which is currently in its final phases of construction at BESSY II. Here, the photons fly from the sample to the detector.

The green arm of the new METRIX instrument, which is currently in its final phases of construction at BESSY II. Here, the photons fly from the sample to the detector. © HZB / M. Setzpfandt

Annette Pietzsch has many jobs: the physicist develops instruments for BESSY II that researchers can use to observe how molecules interact with each other. She mostly prefers to use the instruments to do her own research. This is what brought her from Sweden to HZB ten years ago.

Annette Pietzsch chose the bright green colour very much on purpose: you can’t miss the long arm of the new METRIXS instrument reaching into the experimental hutch. It had to be anything but boring grey or stainless steel, which there is already plenty of in the experimental hall. The physicist is currently building a new instrument at the synchrotron BESSY II. The massive components were just recently hovered in spectacularly through the roof and are now freshly assembled. Only the centrepiece, the vacuum chamber for the samples, still hides away in its giant cardboard box. The team has a lot of work lined up next week, but they are looking forward to it eagerly: because the green instrument can then be used to study liquids with inelastic X-ray light. It is the only instrument of this kind that is optimised for liquid samples – and is a world innovation.

More than one job

Building up an instrument is a full-time job. But, at the same time, Annette Pietzsch is also involved in the development of another instrument, the meV­RIXS. This is currently in its final test phase, in which everything is being precisely adjusted to ensure the instrument works perfectly when it goes online. Yet she has many other jobs on top of that. One of them is especially important to her: her own research, for which she is regularly using the instruments to run her own experiments. And if there’s time, and she isn’t fully busy with the METRIXS, she becomes a supervisor again for the guest researchers experimenting at BESSY II. Recently, she was entrusted with more duties still, as the employee representative on the HZB Supervisory Board. “What I didn’t think of when applying for the supervisory board was the additional time for the board work. Now, I’m not only on the supervisory board, but am also a guest on the Science and Technology Board (WTR) and on the scientific advisory board,” she declares with a wry smile.

This is all in addition to having three children at home, 6, 12 and 15 years old. She has to organise and constantly juggle all kinds of everyday tasks, and not only in times of pandemic. Despite this, she never seems stressed, and knows how to take her time. Annette Pietzsch has tied her hair up into a loose ponytail and is wearing a colourful knitted sweater. The physicist has been working at HZB for nearly ten years. Originally, she wanted to study astronomy, to observe the stars and the sky. But after a visit to the Hamburg synchrotron radiation laboratory HASYLAB, she changed to surface physics and later to molecular physics. “I’m not a night person at all and, as an astronomer, I would have had to work mostly nights. So, looking back, it was a good decision,” she says.

The Swedish adventure – and why it ended

After her physics studies, Pietzsch went on to do her doctorate in Hamburg, after which she packed her bags and moved to work as beamline supervisor for several years at the Swedish synchrotron MAX­Lab. “That was a great time. My two sons were born in Sweden, learned the language from when they were small, and now go to a school in Wilmersdorf that offers additional classes in Swedish.”  Even though the family felt quite comfortable in Sweden, in 2012, she decided to return to Germany. Pietzsch had already had contact with Alexander Föhlisch’s workgroup at HZB during her time in Hamburg. Suddenly, the opportunity for a position in Berlin arose, and she thought: “Hey, I can have the same kind of job in Germany, too.” What attracted her most was that she could do more of her own research. “In Sweden, user service had priority over everything; here it is more balanced.”

Researching where physics meets chemistry

Today, she researches at the Institute Methods and Instrumentation for Synchrotron Radiation Research, where physics meets chemistry. She examines functional materials such as liquids, gases or metal complexes that have interesting properties. She also works on everyday substances like water. Although water is everywhere, we understand only little about its behaviour so far, and there are conflicting schools of thought. “I find it exciting that we can research fundamental phenomena of our world at BESSY II,” she says.

Pietzsch needs suitable methods for these experiments – and that brings us back to the bright green METRIXS. The instrument is specialised for studying liquids using inelastic x-ray scattering. This makes it possible to study molecular reactions in situ, where they normally occur, and how the chemical environment influences the molecules. This way, researchers can gain new insights into how chemical reactions occur at the elemental level and could then be tweaked in new ways. The conventional study methods look at crystals, but if the substances occur in nature dissolved in liquids, then there is even more to be gained from studying them in that environment as well. “It’s a bit like: either you study a living fish as it swims in water, or you study a dead fish out of water. In both cases, you learn something about the fish, but it’s different things that you discover.”

At one time, Pietzsch used to travel to the Paul Scherrer Institute in Switzerland to do her experiments, but her requests were not exactly popular there. They often feared that the liquids she was studying could contaminate the vacuum. “Solid samples are simply more practical to handle in experiments,” she explains. Eventually, Switzerland flatly turned her down. That motivated the physicist to simply develop the right kind of instrument herself at BESSY II – and the result is now the new METRIXS.

Overcoming challenges with good team work

Of course, Annette Pietzsch does not do all of this alone; rather she works in a widely diversified team. Behind her organisational talent is a healthy attitude towards her own limits: “I don’t have to do all things myself if there are specialists who can do them. If you become a jack of all trades, at some point you’re no longer enough of a specialist for one thing.” She relies on cooperation in her research, too. A theoretician has just recently joined her team. “When we are all together in one place and holding discussions, we learn to understand the others’ way of seeing things. That is incredibly fruitful,” she relates. 

Frustration opens new paths

There is yet another thing important in her job: scientists have to be tolerant of frustration. Often, things don’t go according to plan; experiments fail despite having prepared them for so long – as Annette Pietzsch personally experienced already early in her career. She had to change the topic of her doctorate after only two years because the nanoparticles she was studying could not be reproduced reliably. She swallowed the bitter pill and went back to square one. This experience did not hurt her, she wants to assure other doctoral candidates as well. Sometimes, you hit a dead end, but you should not let that scare you off. Because there is always another way. Those who can cope well with failure as a scientist have most definitely found one of the most exciting and fulfilling jobs in the world.

Silvia Zerbe

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