Professor Lutz Koepke at the South Pole. He and his team are hoping to prove the existence of neutrinos in far-away galaxies with the Ice Cube project.
New Window on the Universe
IceCube is an international project based near the South Pole and aimed at conducting further research into neutrinos – a new window on the universe. The team headed by Prof. Lutz Koepke of the Institute for Physics at Johannes Gutenberg University in Mainz plays a key role in this project.
Professor Koepke, all over the world, neutrino research is being pursued at great expense. What makes neutrinos so interesting, and research into them so important?
Koepke: For around 30 years we have had a successful Standard Theory of elementary particles and the forces that act between these 12 basic components of matter. Neutrinos play a very special role. They are the only particles that engage exclusively in weak interaction. This makes them particularly suitable for investigating this type of interaction. We are not entirely happy with our Standard Theory, even though it has described measurements extremely well so far. We know already that neutrinos contradict the Standard Theory in that they possess a minuscule mass. However, as yet we are unable to attribute a precise value to it. This fact can influence the entire universe, its development and end, and even the structures observed. I am always fascinated by how the smallest, lightest particles can influence the whole world!
IceCube certainly has an extraordinary location. What are the project’s other special features, and what results are you hoping for?
Koepke: Scientists have been saying since the 1950s that it should be possible to detect transitory neutrinos astronomically. After many failed attempts, neutrino telescopes have been in operation in Lake Baikal and at the South Pole for some years. They function very successfully, but to our great regret, no neutrinos from other galaxies have been discovered so far! It is now clear that building the 200 times more powerful and more sensitive IceCube telescope is technically and financially feasible. Theoretical estimates assure us that such a telescope ought to enable us to detect neutrinos from distant galaxies. Then we can solve the riddle of the origin of ultra high-energy cosmic radiation, and study processes in the vicinity of black holes.
There is talk of all the photomultipliers being surrounded by “Duran” flasks. What is the function of these capsules?
Koepke: Pressure beneath the 2,000-meter-thick ice shelf is 200 times as high as in the atmosphere above. The sensitive photomultipliers and electronics have to be protected. High-durability “Duran” borosilicate glass is an obvious choice for the pressure flask. We are very pleased that SCHOTT is developing a type of glass for us that is permeable to ultraviolet rays, with 50% higher permeability for the weak “neutrino flashes.”