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| Searching for the Universe, from an Iron Mine |
| Dr. Steve Leman |
| Thursday, Jan 12, 2012 at 8:00 PM |
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| We understand the nature of only 4% of the universe - stars, gas, rocks, you, and me - so called baryonic matter. Precision astrophysical measurements and detailed modeling allow us to understand that 23% of the universe is comprised of material that helped form the earliest galaxies and today affects the orbital dynamics of galaxies and galaxy clusters - dark matter. It is invisible yet interacts gravitationally. On large scales, its gravitational effects dominate that of the ordinary matter. The remaining 73%, termed dark energy, is pushing galaxies apart at an accelerating rate and will lead to a cold death of the universe.
Our galaxy, the Milky Way, is believed to exist within a much larger dark matter structure, and we move through it relatively unimpeded. This allows us to set up detectors here on earth and search for dark matter signals. Our group works on one such experiment, the Cryogenic Dark Matter Search, located in an inactive iron mine in Soudan, Minnesota.
The main theme of this talk will focus on motivation for the dark matter hypothesis, our dark matter search experiment's design, detectors, and search results. People of all backgrounds are invited and no background knowledge in astro-particle physics is needed.
Speaker Bio
Steve Leman presently works on the Cryogenic Dark Matter Search (CDMS) and Micro-X Microcalorimeter X-ray Telescope experiments at the Experimental Cosmology and Astrophysics Laboratory at MIT. He founded and continues a leadership role in the CDMS detector Monte Carlo group through its studies of the experiment’s novel gamma/neutron detectors. This work involves detailed modeling of phonon and charge transport physics in cryogenic germanium detectors in support of detector characterization, design, signal processing, and data analysis. In Micro-X, he designed and tested multiple subsystems and participates in integration of the instrument. Previous work has included novel silicon and germanium X-ray imaging spectrometers for astrophysical observations along with gamma-ray detectors for positron annihilation spectroscopy. His work combines theoretical and computational ability with hands-on laboratory work.
Please join us for a pre-meeting dinner discussion at Changsho, 1712 Mass Ave, Cambridge, MA at 6:00pm before the meeting. |
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