Ideal Setting For Sensitive Experiments

Good things come to those who wait - especially when it comes to world-class research infrastructure. The idea for the HPQ building was first floated in 2010 as a replacement for the two existing 1960s physics buildings, which were no longer suitable for modern research needs. Today, 16 years on, the HPQ project on the Hönggerberg campus is still very much a construction site, though the excavation pit is now considerably shallower than it was when work began four years ago. By this June, work was already well under way on the second basement level, with the shell of the first above-ground floors scheduled for completion by the end of the year. From 2030, some 500 researchers and staff are due to move into the building, which will provide 8,000 square metres of lab space and 4,000 square metres of office space. It will accommodate around 22 professorships from the Department of Physics, along with researchers from other departments.

The HPQ will be one of the world's few research facilities to feature labs specifically built for physics experiments that require an exceptionally stable environment. Experimental physics now delves into phenomena on ever-shrinking scales of length and time - in the field of quantum computing, for instance. It only takes the slightest vibration, magnetic influence or temperature fluctuation to distort such measurements. That's why the project began not with architectural considerations, but with a question: what infrastructure and technical conditions will future research require?

A participatory process

"The new building grew directly out of the research needs," says Janis Lütolf, head of technical services at the Department of Physics and the department's deputy managing director. "The professors were heavily involved in planning right from the word go."

The project was based on a scientific concept paper drawn up by a small in-house ETH team led by then head of department Gianni Blatter. Running to some 40 pages and including input from experts, the paper systematically set out the requirements of the various research groups and translated them into concrete specifications for the architectural competition. The HPQ is the first ETH Zurich building to be planned using this method.

To create the concept paper, the HPQ team held in-depth discussions with numerous professors and visited leading research facilities across the US, the UK and Germany, where they compared notes with researchers and planners. "We learned two key lessons: decoupling the building from its own vibrations is imperative and having a standardised room layout is genuinely useful," says Lütolf. Thanks to the modular design, labs in the HPQ can subsequently be slotted together as needed or adapted to new research requirements. "The flexible configuration and standardised systems will create all sorts of synergies," he adds. "And that will make maintenance considerably simpler and cheaper than it is today." The team also carried out its own measurements in existing buildings to find out just how sensitive the research groups' experiments are to different environmental factors such as temperature or vibration.

Based on the finished concept paper, ETH launched a two-stage project competition. Some 50 interdisciplinary teams took part in the first round, bringing together specialists in architecture, urban design, civil engineering and building services. Ten went on to produce a design for the second round, with the jury eventually opting for Zurich-based architecture firm Ilg Santer Architekten. Their winning entry has been taking shape since 2022.

Building understanding

Scientific requirements dictate the design of the entire building. Labs for sensitive experiments that need a controlled environment will be housed in a six-storey basement complex extending up to 28 metres below ground. There, scientists plan to develop new materials, computer chips and components for quantum computers controlled by single photons. In the Center for Low Noise Experiments (CLNE), located on the deepest level, the research equipment will sit on concrete plinths weighing up to 120 tonnes. Active air springs will mechanically decouple the instruments from the rest of the building and prevent vibrations from being transmitted. The temperature must vary by no more than 0.01 degrees Celsius in the highly insulated labs, and vibrations may not exceed 0.1 micrometres per second.

"Dozens of specialist planners from different companies are involved in delivering the HPQ," Lütolf says. "They are responsible for areas such as lab construction, architecture, structural engineering and building services, but the vast majority of them had never set foot in a physics lab before." Prior to the start of the planning process, a walk-through day was therefore organised at the existing physics buildings. This enabled planners to see the existing facilities for themselves and to ask researchers questions one on one. "That was hugely important for building an understanding of what researchers need. It also meant people got to know each other before the first challenges cropped up," explains Lütolf. This close working relationship has proved equally important during the planning and construction phases, especially as new challenges continue to emerge to this day. "There's a great deal of interest among researchers in how construction is progressing," says Lütolf. "It's all been designed specifically with their needs in mind, so they're really keen to see how much it will support their research over the coming decades."