P. Buford Price
Professor in the Graduate School
Neutrino Astrophysics, Paleoclimatology, and Life in Extreme Environments

Group Site: http://icecube.berkeley.edu
MORE on my research: http://icecube.berkeley.edu/~bprice/

Research Interests

My interests as an experimentalist are broad. I like to develop projects that cross traditional disciplinary boundaries. The projects in which my students, post-docs and I are engaged involve developing and exploiting novel instruments that probe polar ice down to depths of thousands of meters as well as those that use fluorescence microscopy to search for life in deep ice.

Current projects

IceCube High-Energy Neutrino Observatory

My former students and I, in collaboration with a group at U. of Wisconsin, conceived the AMANDA project (Antarctic Muon and Neutrino Detector Array). AMANDA, installed in South Pole ice at depths 1500 to 2300 m, has been operating since 2000. In order to search for the very low flux of cosmic neutrinos with energy up to ~1016 eV, we and an international consortium are building the IceCube observatory, which surrounds AMANDA and will instrument a volume of 1 km3 with eighty strings, each containing 60 optical modules at depths from 1400 to 2400 m. The first 22 strings are now installed and operating in conjunction with the 19 AMANDA strings. It now forms the central part of IceCube, the world’s largest neutrino observatory. With IceCube we detect ultrahigh-energy neutrinos passing upward through the entire earth. It can answer fundamental questions in astrophysics (the nature of blazars and of gamma ray bursters), cosmology (the nature of the dark matter that comprises the majority of the mass of the universe), cosmic ray physics (origin of the highest energy cosmic rays), and particle physics (properties of neutrinos including their oscillations and their behavior in a gravitational field). IceCube will be completed in 2011.


Dr. Ryan Bay and I invented an optical dust-logging instrument that fits into deep boreholes in glacial ice and rapidly locates volcanic ash layers, records maxima and minima in the concentration of dust particles corresponding to glacial and interglacial climate, and detects abrupt climate changes with a depth resolution of a few mm. We have discovered that large volcanic eruptions correlate with abrupt climate changes of as much as 20 degrees Celsius, and that many volcanic signatures in deep ice match up in both hemispheres and across the continent of Antarctica. To achieve the best possible angular resolution of sources of high-energy neutrinos, we use the dust logger in a number of boreholes to map the three-dimensional distribution of dust and ash in the 1 km3 volume of IceCube.

Life in Extreme Environments

My students and I have shown that micron-size bacteria and archaea survive for more than 105 years at temperatures down to -50°C in glacial ice. We have found that occasional excesses of methane, nitrous oxide, and heavy oxygen (18O) in Greenland glacial ice are produced by localized excesses of certain microorganisms blown onto growing icecaps during severe storms. With scanning fluorimeters, we are mapping microbial distributions down the depths of ice cores from Greenland and Antarctica. We think the extremely variable arrival rates of clusters of microbes provide a record of meteorological events in the last 105 years.

We have designed and built biologging instruments that detect biomolecules present in amino acids and in specialized microbes such as methanogens. These instruments make it possible to detect as few as 1 microbial cell per cm3 in ice. They can be adapted to future missions to Mars, where methane emission has recently been detected.

Selected Publications

P. B. Price, “Comparison of optical, radio, and acoustical detectors for ultrahigh-energy neutrinos,” Astropar. Phys.5, 43 (1996).

P. B. Price and L. Bergström, “Optical properties of pure ice at the South Pole: scattering,” Appl. Opt.36, 4181 (1997).

L. Bergström, P. B. Price, et al., “Optical properties of pure ice at the South Pole: absorption,” Appl. Opt.36, 4168 (1997).

Y. D. He and P. B. Price, “Remote sensing of dust in deep ice at the South Pole,” J. Geophys. Res.103, 17041 (1998).

P. Buford Price, “A habitat for psychrophiles in deep Antarctic ice,” Proc. Natl. Acad. Sci. USA97, 1247 (2000).

P. B. Price, K. Woschnagg, and D. Chirkin, “Age vs depth of glacial ice at South Pole,” Geophys. Res. Lett.27, 2129 (2000).

Kurt Woschnagg and P. Buford Price, “Temperature dependence of absorption in ice at 532 nm,” Appl. Opt.40, 2496 (2001).

Predrag Miocinovic, P. Buford Price, and Ryan C. Bay, “Rapid optical method for logging dust concentration versus depth in glacial ice,” Appl. Opt. 40, 2515 (2001).

E. Andrade, et al. (125 authors), “Observation of high-energy neutrinos using Cerenkov detectors embedded deep in Antarctic ice,” Nature 410, 441 (2001).

P. B. Price et al., “Temperature profile for glacial ice at the South Pole: implications for fife in a nearby subglacial lake,” Proc. National Academy of SciencesUSA99, 7844 (2002).

J. Ahrens et al., “Limits to the muon flux from WIMP annihilation in the center of the earth with the AMANDA detector,” Phys. Rev.D66, 032006 (2002).

A. J. Westphal, P. B. Price, T. J. Leighton, and K. E. Wheeler, “Kinetics of size changes of individual Bacillus thuringiensis spores in response to changes in relative humidity,” Proc. Natl. Acad. Sci.USA 100, 3461 (2003).

J. Ahrens et al. (the AMANDA collaboration), “Limits on diffuse fluxes of high energy extraterrestrial neutrinos with the AMANDA-B10 detector,” Phys. Rev. Lett.90, 251101 (2003).

J. Ahrens et al. (AMANDA Collaboration), “Search for extraterrestrial point sources of neutrinos with AMANDA-II,” Phys. Rev. Lett.92, 071102 (2004).

R. C. Bay, N. Bramall, and P. Buford Price, “Bipolar correlation of volcanism with millennial climate change,” Proc. Natl. Acad. Sci. USA101, 6341 (2004).

P. Buford Price and Todd Sowers. “Temperature dependence of metabolic rates for microbial growth, maintenance, and survival,” Proc. Natl. Acad. Sci. USA101, 4631 (2004).

H. C. Tung, P. B. Price, N. E. Bramall, and G. Vrdoljak.” Microbes metabolizing on clay grains in 3-km-deep Greenland basal ice. Astrobiology6, 69-86 (2006).

R. C. Bay, N. Bramall, P. B. Price, G. Clow, R. Hawley, R. Udisti, and E. Castellano,” Globally synchronous ice core volcanic tracers and abrupt cooling during the Last Glacial Period. J.Geophys. Res.111, D11108 (2005).

P. B. Price, “Attenuation of acoustic waves in glacial ice and salt domes”, J. Geophys. Res.111, B02201 (2006).

C. Tung, N. E. Bramall, and P. B. Price, “Microbial origin of excess methane in glacial ice and implications for life on Mars,” Proc. Natl. Acad. Sci. USA102, 18292 (2005).

P. Buford Price, “Science and technology with nuclear tracks in solids,” Radiation Measurements40, 146 (2005).

M. Ackermann et al., “Optical properties of deep glacial ice at the South Pole,” J. Geophys. Res.111, D13203 (2006).

A. Achterberg et al., “Limits on the high-energy gamma and neutrino fluxes from the SGR 1806-20 giant flare of 27 Decemer 2004 with the AMANDA-II detector,” Phys. Rev. Lett. 97, 221101 (2006).

A. Achterberg et al., “Limits on the muon flux from neutralino annihilations at the center of the Earth with AMANDA,” Astroparticle Phys. 26, 129 (2006).

A. Achterberg et al., “On the selection of AGN neutrino source candidates for a source stacking analysis with neutrino telescopes,” Astroparticle Phys. 26, 282 (2006).

A. Achterberg et al., “First year performance of the IceCube neutrino telescope,” Astroparticle Phys. 26, 155 (2006).

P. Buford Price, “Microbial life in glacial ice and implications for a cold origin of life,” FEMS Microbiol. Ecol. 59, 217 (2007).