Nobel Prize winner on the Hafelekar – the Victor Franz Hess measuring station

It's not exactly one of those days when I want to jump on the Nordkettenbahn cable car to ride up to the Hafelekar and enjoy the gigantic view of the city. It's been foggy, rainy and cold for days - that means winter conditions at an altitude of over 2,000 meters, snow, ice and perhaps sub-zero temperatures. That means boots, a weatherproof jacket, hat and scarf.

But the newly renovated "Victor Franz Hess measuring station" will open on the Hafelekar on September 29, 2022. And I want to be there. Alongside the Historic Observatory, it is one of Innsbruck's architectural gems that I hope attracts a lot of attention - and that has made scientific history.

So up with the Hungerburgbahn and on with the cable car to the Seegrube, towards the Hafelekar. In the snow, the unspectacular hut a few minutes' walk above the mountain station looks even more inconspicuous. To the right is the Hafelekarspitze, normally also a walk, but in this weather on slippery ground not exactly what my heart desires. When the fog lifts a little, the view is amazing.

Originally, the university measuring station was a construction hut for the Nordkettenbahnen, which opened in 1928. In the 1930s, Victor Franz Hess continued the measurements here for the discovery that would fundamentally change our view of the universe. In 1911/12, Hess flew in a balloon to an altitude of around 5,000 meters to provide evidence of cosmic radiation. It was a groundbreaking discovery that opened up various new fields of research and continues to drive forward important investigations in physics to this day.

The small wood-paneled rooms were not made for many people, but they were ideal as a measuring station. The sensitive devices could be brought up by train and the station could be reached in a short time, even in winter. Ideal conditions and one of the reasons why Victor Franz Hess accepted a position at the University of Innsbruck in 1931.

in1936, Hess was awarded the Nobel Prize for the discovery of extraterrestrial radiation, and the following year he accepted a professorship in Graz. The fact that the Austrian quantum physicist and recent winner of the 2022 Nobel Prize in Physics, Anton Zeilinger, also researched and taught in Innsbruck from 1990 to 1999 shows what a good reputation the University of Innsbruck still has in this field today.

During the Nazi era, Hess emigrated to the USA and became a US citizen. After the war, the world-famous scientist visited Innsbruck three more times. in 1958, he was awarded an honorary doctorate from the University of Innsbruck. The day before his 75th birthday, he stood one last time on the Hafelekar, in "his" measuring station.

To underline the importance of the physicist and the measuring station, the university, the city of Innsbruck and Nordkettenbahnen have renovated the historic building. The opening marks the 90th anniversary of the commissioning of the measuring station and celebrates Victor Franz Hess' milestone birthday in 2023.

Visitors can learn interesting facts about the researcher's work and the function of the measuring instruments at two stations. On one side, there are holographic projections that illustrate scenes from the life of the Nobel Prize winner. On the other side, an animated film explains the Steinke apparatus, which has also been restored. It was one of the central instruments, as it enabled the automated continuous registration of cosmic radiation. This allowed measurements to be taken for three days without maintenance.

For the time being, access to the premises is reserved for university specialist groups. A bit of a shame, but perhaps that will change. At any rate, the participants were able to take a look inside the hut at the opening. The rooms exude a special atmosphere. They have been preserved in their original state and provide an insight into early research activities in the field of cosmic radiation.

On the walls are display boards describing the life, work and achievements of Victor Franz Hess and placing them in the context of the history of science. There are also numerous photo reproductions and the scientist's desk.

In addition to Hess, the research site on the Hafelekar was also used by other researchers for their investigations. In 1937, Marietta Blau and Hertha Wambacher were able to observe how a cosmic ray particle smashed an atomic nucleus on photographic plates exposed here. In the 1960s and 1970s, a neutron monitor and muon detectors were in operation at the measuring station. With these, the two researchers were able to individually measure two types of particles contained in the cosmic rays and make further important observations.

The Victor Franz Hess measuring station is still in use today. The data is now sent digitally to the respective research groups.

On the occasion of the opening at the end of September, the European Physical Society (EPS) awarded the measuring station the title of EPS Historic Site. The internationally active organization has around 80 member societies and research institutes, as well as individuals. In total, EPS represents around 130,000 scientists from all over the world, as the EPS representative present, Rüdiger Voss, noted.

With the plaque, the Victor Franz Hess measuring station is now one of the outstanding historical sites of physics internationally. A total of 56 facilities have received this award to date. The Hafelekar is the third in Austria and the first outside of Vienna (Institute for Radium Research Vienna, Atomic Institute of the Vienna University of Technology).

The Victor Franz Hess measuring station, this simple wooden hut high above Innsbruck, is once again making scientific history. Renovation and a contemporary visitor information center underline the importance of the place. The Hafelekar has always been a place to go, a place to know in Innsbruck - now there is another attraction at an altitude of 2,300 meters.

Victor Franz Hess measuring station

A few minutes' walk north of the Hafelekar/Nordkettenbahnen mountain station

From Innsbruck, take line J or the Hungerburgbahn to the Nordkettenbahnen valley station and then continue via the Seegrube to the Hafelekar.

Can only be visited from the outside!

Further information at www.uibk.ac.at

Photos, unless otherwise indicated: © Susanne Gurschler

Information on other sights in Innsbruck can be found at www.innsbruck. info.