Stéphane CoutuProfessor of Physics and of Astronomy and Astrophysics
The Pennsylvania State University
Ph.D., California Institute of Technology, 1993
Office: 303H Osmond Lab: (814) 865-2015
|Photo taken at Happy Camper School (survival training course) on the Ross Ice Shelf in Antarctica, January 2010, in preparation for the recovery operations of the CREAM-V balloon payload.||
Penn State Institute for Gravitation and the Cosmos
Penn State Center for Particle Astrophysics
Physics 457 Laboratory,
Spring 98, Fall 98, Fall 01, Fall 02.
Physics 237 Introduction to Quantum Physics, Spring 99, Fall 99.
Physics 211 General Physics: Mechanics, Spring 00, Fall 00, Fall 03, Spring 06, Spring 07, Spring 08, Fall 08, Spring 11, Spring 12, Spring 13, Spring 14, Spring 15, Fall 15, Spring 17
Physics 559 Graduate Laboratory, Spring 01, Spring 02, Spring 03, Spring 05.
Physics 590 Current Research (Graduate Seminar), Spring 01, Spring 02, Spring 03, Spring 05.
I am interested in experimental high-energy particle astrophysics, which is the study of the universe at the point where the mind-boggingly vast meets the infinitesimally tiny. I have been studying high-energy cosmic rays, particles that rain down on Earth from the depths of space. Among these are particles of antimatter, which can be used to search for candidates for the elusive dark matter that pervades the universe but is detectable, at present, only through its gravitational influence. Or else they can point to new and interesting mechanisms for particle production and acceleration within the Galaxy. At the very highest energies, an entirely different and essentially unexplored regime opens up, with particles most likely originating from outside our own Galaxy, and carrying more energy than ever achieved artificially in the laboratory by particle accelerators.
|I am involved in the Pierre Auger Observatory project. This is an ambitious plan to construct two huge arrays of detectors, one in the northern hemisphere, and one in the southern. These arrays study the highest-energy particles in the Universe, and open up a new window on the physical world. Although these particles are very rare (and therefore require very large arrays of sensitive detectors), they are known to exist from previous measurements done by smaller detectors. At present it is not known how such tremendous energies can ever be attained, and the Auger observatory will provide information crucial to the resolution of the puzzle of their existence. The southern detector site is currently completed and operating in Western Mendoza Province, Argentina. A northern array is considered for deployment in Colorado. My Penn State colleague Paul Sommers is one of the founding fathers of this large international project.|
|The Pierre Auger Observatory and its science can be explored using 3D structures viewed in Google Earth. The model files are available here. Our activities on the project are supported by the National Science Foundation. Click on the image at left to download an animated video of a Google Earth exploration of Auger.|
I am involved in the Cosmic Rays Energetics And Mass (CREAM) project. This is a NASA-sponsored program of studies of high-energy cosmic rays up to the astrophysical "knee" (a spectral feature at an energy of a few times 1015 eV). After 100 years of studies since their initial discovery by Victor Hess, their exact origin (probably supernova remnants) has still not been unambiguously resolved, and increased experimental measurements are required. Direct measurements at such high energies are difficult because of very small particle rates. To remedy this, CREAM achieves long exposures by flying repeatedly on long-duration high-altitude balloon flights in Antarctica. The cosmic-ray nuclei ranging from hydrogen to iron are individually identified and counted, and their energy measured up to hundreds of TeV (a few times 1014 eV), approaching the important knee energy. Click on the image at left for video footage of a CREAM launch in Antarctica.
I am involved in the Cosmic
Ray Electron Synchrotron Telescope (CREST) experiment. This
is a NASA-sponsored project to fly a novel instrument on
high-altitude balloons in Antarctica in an attempt to detect
cosmic-ray electrons at energies beyond about 2 TeV (2 x 1012
eV), where they have never been detected. Such electrons would
have to come from a relatively local neighborhood of our Galaxy,
from sources such as supernova remnants, and their detection would
reveal such sources and provide new insights into the high-energy
Universe. Click on the photo to the left for a video of the late
December 2011 CREST launch from McMurdo Station, Antarctica.
|I was involved in the NASA-supported High-Energy Antimatter Telescope (HEAT) program, a series of high-altitude balloon-borne experiments to study antimatter in the primary cosmic radiation. We studied high-energy positrons and antiprotons using two different instruments between 1995 and 2004. We used large and complex detectors with redundant particle identification techniques to unambiguously select out the particles of interest from a large background of ordinary cosmic-ray protons and nuclei. We flew such instruments to the very edges of the atmosphere, essentially into space, by means of enormous helium-filled balloons launched from Ft Sumner, NM and Lynn Lake, Manitoba, Canada. Click on the left for video footage of the HEAT 1994 balloon campaign in Ft Sumner (beware, this is a large file, about 117MB).|
|I also participated in the Monopole, Astrophysics, and Cosmic Ray Observatory (MACRO) project, an experiment buried deep under a mountain in Italy. The experiment shut down at the end of 2000. MACRO was a very large instrument, 10 meters-high by 12 meters-wide by 72 meters-long, using multiple particle tracking and identification techniques to study those particles capable of traveling through more than 1000 meters of rock. Among the many physics topics covered by this multi-purpose detector was the search for magnetic monopoles, hypothetical particles that would carry magnetic (instead of electric) charge, and that are predicted by some theories but have never been observed experimentally. When cosmic rays strike the Earth's atmosphere after traveling through the Galaxy for many millions of years, they generate a cascade of atmospheric secondary particles, known as an air shower. MACRO studied the very penetrating muon components of air showers, and this information in turn, sometimes combined with measurements at the mountain surface by the separate EAS-TOP experiment, was used to infer the mass of the primary cosmic rays that initiated the air showers. By looking at muons traveling upwards, MACRO detected neutrinos that interacted in the rock underneath the detector. Such neutrinos could arise from dark matter particle annihilation at the center of the Earth or the Sun. Finally, MACRO searched for bursts of neutrino events arising from supernova explosions in our Galaxy.|
A few representative recent articles are listed below. A full list of my refereed publications is also available.