News & media

Researcher Profile: Olga Botner

Olga Botner shows a model of how IceCube uses light signals in the ice. This year’s Nobel Prize in Physics is also about light: the blue light-emitting diode that has given us the LED bulb. Photo: Mikael Wallerstedt

FASCINATED BY THE BIG QUESTIONS

Olga Botner, Professor of Physics, is among the Uppsala researchers who help to select Nobel Prize winners. It enables her to learn more about other people’s research fields and investigate her own in depth. Hers is about particles from space that have been found deep down in the ice at the South Pole.

Most people follow the prizegiving ceremony and the Nobel Prize banquet from the TV sofa, but Olga Botner is one of the invitees. Since 2001, she has been a member of the Royal Swedish Academy of Sciences, in the committee that appoints the Physics Prize winner. It is a task she appreciates immensely.

‘First, it’s a tremendous honour to be one of the world’s seven committee members who can join in selecting the Physics Prize winner. Second, I get the chance to learn about physics other than the kind I do. I get to learn about other people’s research fields and explore my own in depth. It’s a privilege to have this chance. And the Nobel banquet is the icing on the cake.’

In 2014, the Nobel Prize in Physics went to three Japanese researchers: Isamu Akasaki, Hiroshi Amano and Shuji Nakamura, for their discovery of the blue light-emitting diode that subsequently led to the development of energy-saving LED lamps.

‘It’s really in line with Alfred Nobel’s will,’ she says. ‘For one thing, the Physics Prize is intended to be for a discovery or invention; for another, it’s supposed to improve the world in some sense.’

Outside the Nobel context, too, Olga Botner has many international contacts. She is the spokesperson for the IceCube project, with 300 researchers from about ten countries.

In November 2013, they made a discovery that resounded around the world. Deep down in the South Pole ice, the researchers found traces of ‘neutrinos’, particles that originated outside our Solar System.

‘It’s tremendously exciting. For the first time, we have convincing evidence that high-energy neutrinos from outer space have landed here on Earth,’ Botner says.

Dubbed the 2013 Breakthrough of the Year by the UK publication Physics World, this discovery marks not only a major scientific step forward but also a triumphant culmination of six years’ toil. This is how long it took to establish the IceCube South Pole Neutrino Observatory. There, more than 5,000 digital optical modules (DOMs) have been sunk in a cubic kilometre of inland ice.

Two years after the IceCube facility was completed, the scientists have now had confirmation that the technology works and the neutrinos can actually tell us something about the universe.

‘This may be the start of a completely new line of work in astronomy,’ Botner says.

She has been in the project since 1998, when the first prototype Antarctic Muon And Neutrino Detector Array (AMANDA) was built at the South Pole. But the project dates back further than that. The idea that neutrinos could teach us something about the universe arose in 1960.

‘Even then, people grasped the scope and potential of studying them, but didn’t know how to go about it.’

The first key choice was to use ice. Since neutrinos extremely seldom interact with other particles, they need to be studied in a ‘dense’ material containing numerous atomic nuclei. It has to be transparent too, since neutrinos have no electric charge and are visible only when they collide with other particles. There is then a ‘shower’ of charged particles — flashes of light that are visible if the medium is transparent enough.

Altogether, 5,160 optical sensors have been placed in the ice. For two years, they have detected 28 events. Roughly half of these are neutrinos, in all probability derived from space — as their energy level shows.

Research on various astronomical phenomena, in this extremely inaccessible setting, is now set to pick up. In all these years, Olga Botner has never travelled to the South Pole. Instead, she has followed the project from a distance. But several Uppsala students have been there to help out with snow clearance and other practical tasks.

‘They still talk about it. The project has given pleasure to so many people, not least students.’

After nearly 30 years at Uppsala University, she has a great deal to tell and it is easy to get caught up in her enthusiasm.

‘Why did you choose physics?’

‘I’m fascinated by the connection with the big questions about the universe and its origins. I started with mathematics and have moved towards elementary particle physics, where I get to work on tiny particles (neutrinos) and what they can teach us about the universe.’

Annica Hulth

Facts – Olga Botner

Title: Professor of Experimental Elementary Particle Physics at Uppsala University.
Assignments: since 2001, a member of the Royal Swedish Academy of Sciences; for the past five years, a member of the Nobel Committee for Physics; and spokesperson for IceCube since 2013.
Leisure interests: not very much free time, but likes being out in the countryside. Building a house in Halland, SW Sweden; likes open landscapes and the sea.
Last book read: Martin Gardner’s autobiography, Undiluted Hocus-Pocus.
On the 2014 Nobel Physics Prize: ‘If the last one was the century of the electric light bulb, this century will be the one of the LED lamp. LEDs can be used even in parts of the world where there is no electricity, so people can go straight from paraffin lamps to LEDs.’