![\"black](\"https:\/\/www.newsbeep.com\/nz\/wp-content\/uploads\/2026\/10\/prince_buford-crop.jpg\")
The late P. Buford Price, professor of physics, who collaborated with Francis Halzen in the 1990s and early 2000s to create a neutrino observatory in the glacial ice of Antarctica.<\/p>\n
Jane Scherr for UC Berkeley<\/p>\n
The Wisconsin\/Berkeley collaboration began in the 1980s between Halzen and late Berkeley physics Professor P. Buford Price<\/a>, who at the time was studying cosmic rays \u2014 another type of particle whose origins, at the very highest energies, are unknown.<\/p>\n When Halzen conceived the idea of turning the clear ice covering Antarctica into a high-energy neutrino detector, Price and his team were intrigued.<\/p>\n \u201cBuford was just an original thinker,\u201d said Steven Barwick, a UC Irvine professor of physics who at the time was a graduate student and then postdoctoral fellow in Price\u2019s lab. \u201cHe just liked doing new things, looking for new particles, looking for new detector schemes. I think this was just a perfect merging of those interests. And it was a perfect match to Francis\u2019 ideas, because Francis was very forward looking too. I think they just were kindred spirits.\u201d<\/p>\n The project may also have appealed to Price as a novel way to tackle the mystery of cosmic rays. It\u2019s hard to trace cosmic rays to their source because they are charged particles and are easily deflected by magnetic fields in space. But neutrinos travel in a straight line and might be a surrogate for cosmic rays, helping scientists track down their source.<\/p>\n Francis Halzen will deliver Berkeley\u2019s annual Emilio Segr\u00e8 Lecture<\/a> on Nov. 16 in the Chevron Auditorium at International House.<\/p>\n \u201cPeople in Prof. Buford Price\u2019s group \u2026 were among the first to take the whole idea of an ice-based detector seriously,\u201d according to Spencer Klein, a Berkeley research physicist and senior scientist at Berkeley Lab who now leads the two local contingents of the IceCube team.<\/p>\n Another key attraction for Price and his team, Barwick admitted, was that \u201chonestly, a lot of us were just motivated because we didn\u2019t know what we were going to find. And that\u2019s always kind of fun. It was a cool project.\u201d<\/p>\n The plan was to embed cameras in the continent\u2019s solid ice to detect blue light produced when neutrinos collide with other atoms. The collisions produce charged particles, often muons \u2014 essentially heavy electrons \u2014 that are traveling faster than the speed of light in the ice and emit Cherenkov radiation, which is blue.<\/p>\n Not long after Halzen and Price began working together, during a previously scheduled trip to the South Pole to install a cosmic ray detector, Barwick and others in Price\u2019s lab took the opportunity to drill holes in the ice to see whether it was clear enough to transmit light without scattering. The results were mixed \u2014 at the depths they looked, the ice was transparent enough for light to travel long distances, but not clear enough. Bubbles, like those in refrigerator ice cubes, scattered the light. In theory, however, at sufficient depth the bubbles should be squeezed out of existence. Subsequent tests in Greenland in 1991 proved this to be the case \u2014 photomultipliers in the ice could detect Cherenkov radiation produced by muons, though these muons were generated in the upper atmosphere by cosmic rays.<\/p>\n University of Wisconsin-Madison<\/p>\n \u201cThose tests in Greenland and the first tests in Antarctica were unsuccessful by some measures, but established that ice was really, really transparent,\u201d Barwick said. \u201cAnd we knew that at some point the bubbles had to disappear. We just didn\u2019t know quite where.\u201d<\/p>\n That turned out to be about 1.4 kilometers below the Antarctic surface, where scattering was low enough that the team would be able to draw a straight line from the light to the muon to the neutrino and its source in the sky.<\/p>\n \u201cThey (the Price team) then became pioneers in AMANDA, \u2026 which showed that a South Pole neutrino detector was really possible,\u201d Klein said.<\/p>\n Halzen still had to gin up support and funding for the project. Despite proof of concept, many people still had doubts the team would detect anything in ice, as Halzen wrote in 2002 in a series of essays<\/a> about AMANDA. Many people thought very clear ocean or lake water would be better.<\/p>\n Steven Barwick\/UC Irvine<\/p>\n \u201cConvincing donors of the soundness of our idea was no simple matter: I was only a theorist, after all, with no experience building anything, and my collaborators, at least in the beginning, were very talented but very junior physicists at the University of California, Berkeley,\u201d Halzen wrote. \u201cNevertheless, NSF was willing to give us the benefit of the doubt, and within a few years we had joined forces with eight other universities and three research laboratories in Belgium, Germany, Sweden and the United States.\u201d<\/p>\n AMANDA was a cylindrical array of 19 separate strings carrying 677 detectors mounted below the 1.4 kilometer depth Price\u2019s team had identified. AMANDA too detected atmospheric muons, showing the feasibility of the project. With further funding from NSF, the IceCube experiment kicked off in 2004 and incorporated the AMANDA arrays into a much bigger, 91-string array covering nearly one cubic kilometer of ice.<\/p>\n \u201cAMANDA showed the detector was going to work. You just had to build it bigger,\u201d said Barwick, who was co-spokesperson for the experiment. \u201cThis was (part) of the genius of Francis \u2014 he had the perseverance and political savvy to convince the US and international funding agencies to invest in a telescope with much larger size.\u201d<\/p>\n![\"older](\"https:\/\/www.newsbeep.com\/nz\/wp-content\/uploads\/2026\/10\/Francis_16x9_v2-1024x576.png\")
Francis Halzen, professor of physics at the University of Wisconsin, Madison, won the 2026 Nobel Prize in Physics for his leadership of the IceCube collaboration, an experiment in the deep ice of Antarctica designed to detect evidence of high-energy neutrinos.<\/p>\n![\"man](\"https:\/\/www.newsbeep.com\/nz\/wp-content\/uploads\/2026\/10\/kpn2u3-07sciworld1large-copy.jpg\")
Steven Barwick, professor of physics at UC Irvine and a Berkeley PhD, on a ship in the Antarctic.<\/p>\n
![\"bearded](\"https:\/\/www.newsbeep.com\/nz\/wp-content\/uploads\/2026\/10\/IMG_0816-768x1024.jpeg\")
Spencer Klein, a physicist at UC Berkeley and Berkeley Lab, at the South Pole during a visit to work on the IceCube experiment.<\/p>\n