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Royal Holloway University of London Low Temperatures - the posters Low Temperatures Cold on Earth Superconductivity Cryogenics Cold in Space Superfluidity Funded by EPSRC (Partnerships for Public Awareness) Institute of Physics Oxford Instruments Mike Lea, John Saunders, Colin Winterton Rick Marshall Bill Block Bob Lambourne Royal Holloway Oakham School British Antarctic Survey Open University Low Temperatures - the aim To inform and excite interest in students To provide a summary of low temperature research and applications in physics, cryogenic engineering, astronomy, planetary science, medicine and biology To be distributed to schools as A3 posters and A4 summary sheets for individual students from September 2001 Coldest on Earth Vostok Ice Station Plaque commemorating the coldest temperature recorded on Earth View of the main drag • -89.2°C on July 21, 1983 Coldest in the Solar System •Triton - moon of Neptune •Voyager 2: 25 August 1989 •-235°C or 38 K •Pressure 15 bar South Poleon of Triton Triton Tenuous Clouds Surface of Triton Plain of Ice Montage of Neptune and Triton Courtesy of Cosmic Microwave Background COsmic Background Explorer • COBE satellite 1991 • Black Body Radiation T = 2.726 K • Doppler dipole shift T = 3.353 mK • Temperature fluctuations T = 18 K BOOMERANG Telescope • Antarctica 1998 • CMB fluctuations • Flat Universe BOOMERANG maps the Cosmic Microwave Background (CMB) using a balloon-borne telescope that circumnavigates Antarctica. Courtesy of The BOOMERANG Collaboration Coldest in the Universe • The Boomerang Nebula, 5000 light years away, is an expanding cloud of dust and gas from an old star which is collapsing to form a white dwarf. • The expanding gas cools to 1K, the lowest temperature found in the Universe. • A radio telescope in Chile was used to compare signals from carbon monoxide in the Boomerang Nebula with signals from the cosmic microwave background radiation(CMB). The cold region absorbs some of the background radiation. Dr. Raghvendra Sahai, Lars-Ake Nyman, Jet Propulsion Laboratory, NASA Cold wind from The Boomerang Nebula Coldest Laboratory 1 Traditional cryostats Nuclear demagnetisation 150 K Lancaster University Liquid helium: 90 K Copper (electrons): 7 K University of Helsinki Dilution refrigerator Rhodium (nuclei): 100 pK Royal Holloway 5 mK Coldest Laboratory 2 Trapped atom clouds • Laser cooling • Nobel prize 1997 Steven Chu, Claude Cohen-Tannoudji, William Phillips • Magneto-optic traps (MOT) for atoms • 30 nK Na atoms at Stanford Frozen Alive! Ice is lethal to living cells Freeze FreezeAvoidance toleranceto -40°C Antifreeze compounds Ice forms between cellsIce nucleators Glycerol Bacteria Antifreeze proteins Special proteins Inhibit ice growth Cells supercool Avoid ice nucleators Bacteria seed ice formation Treefrog- blue with cold Frozen frogs! Frozen Alive by Janet M Storey Cryosurgery • Cryotherapy uses liquid nitrogen (77 K) • Cancer cells repeatedly frozen and thawed • Rapidly expanding field Courtesy of Royal Surrey County Hospital B r a i n s c a n s Maglev trains Yamanshi - MLX01 • Magnetic repulsion Levitation • Maglev trains 312 mph (Germany) 323 mph (Japan) • Superconducting magnet • Guideway Yamanashi Maglev Test Line Bose-Einstein condensation Atoms in traps BEC Na atoms • Laser cooling • Matter waves = h/p = h/mv • Evaporation • Thermal energy 1 3 mv kT 2 2 • Thermal wavelength h 3kTm • Bose-Einstein condensation a Wolfgang BouncingKetterle Rb atomsMIT - Sussex 2 • T > 30 nK Low Temperatures - the posters Low Temperatures B r a i n s c a n s Cryogenics Cold on Earth Cold in Space Superconductivity Superfluidity For details of how to get the summary sheets and posters call 01784 443448 or e-mail: [email protected] All comments welcome!
