The corona-effect on the ETpathfinder

“The preparations for the arrival of the ETpathfinder have not yet been hampered by the corona crisis. So far we seem to be still right on schedule”, says Prof. Stefan Hild, who is involved in the construction of ETpathfinder, a test facility for the Einstein Telescope that analyses gravitational waves. “Our international team was already accustomed to working together remotely, through video calls—only now everyone calls individually from their own living room instead of in a group from the office. So, the number of screens has increased enormously!”

Started from scratch

Hild made an energetic start last August with an international team of researchers. He had already worked with many of them in Glasgow. Everyone is very enthusiastic about the opportunities in Maastricht. Hild: “The ETpathfinder is a kind of scale model of the Einstein Telescope that we would love to see being built in Limburg hill country. It’s a deep-cooled, triangular underground laser detector that will be able to explore the universe as far back as the Big Bang. It can give an enormous boost to research into gravitational waves and the building blocks of our universe. With the Pathfinder, we’re experimenting with the techniques required for this research, such as laser light and vibration dampers. We started from scratch—from the development of conceptual ideas to a functional design. The challenge lies in fact that we have to push beyond edge of technology on many different fronts and  the many details that we have to pay attention to. Systems from fifteen international partners have to fit together and it has to be right the first time, so that requires a lot of coordination.”

Stefan Hild
Professor Stefan Hild

Optimal working environment

The ETpathfinder is being built in the former transport hall of the Dagblad de Limburger in Maastricht and measures around 800 square metres.  “Here, people can work while maintaining a 1.5-metre distance from each other”, says Hild. “We’re now working on a new vibration-free floor that is separate from the walls. After that, it’ll be on to the clean rooms. The smallest dust particles can already affect the quality of the measurements or even damage the mirrors used to bounce back and forth the laser beams. We also need good vacuum systems for an optimal working environment. All of this high-tech infrastructure comes with a price tag; By the end of this year the first 6 million euros will have been committed.”

No crystal ball

Hild doesn’t dare to predict whether the corona crisis will have a negative impact on the overall project. “It's too early to say at this point. We still have work and plans for the next 20 to 25 years. Naturally, I sometimes worry, but it’s more about the crisis in general and its impact on all of our lives, education and research landscapes and overall the society.”

Staying positive during a crisis

“The bigger the crisis, the more important it is for me to look at the positive aspects. For the environment and climate change, this is in any case a beneficial time. It is amazing to see that many things that seemed impossible so far, currently simply just happen. One of my New Year resolutions for 2020 was to not fly. I took some effort and many long train rides (like going to Vienna, Hamburg, etc.), but now I think I can do that effortlessly for the rest of the year! Although it’s a pity not to be able to visit the LIGO and Virgo detectors in America and Pisa. But with video calling, we can do a lot of research and collaboration. I now have five to ten video meetings a day so I have to pay attention to the balance between work and private life. With two young children in the house and kindergartens and schools closed on the German side of the border, I have to plan carefully. Hats off to all the millions of parents who are now home schooling. And even more respect for the educators who usually do this day in and day out. In the coming weeks, months and years, we will be busy constructing and fine-tuning the Pathfinder. In 2021, we hope to be able to start testing the technologies that will be implemented in the Einstein Telescope from 2030 onwards. There’s still a long way to go.”

By: Josephine Dols-Knegtering, photo Stefan Hild by Philip Driessen