Pumped Helium System for Cooling Positron and Electron Traps to 1.2 K $ Ã J
Nuclear Instruments and Methods in Physics Research A 640 (2011) 232–240 Contents lists available at ScienceDirect Nuclear Instruments and Methods in Physics Research A journal homepage: www.elsevier.com/locate/nima Pumped helium system for cooling positron and electron traps to 1.2 K $ Ã J. Wrubel a, G. Gabrielse a, , W.S. Kolthammer a, P. Larochelle a, R. McConnell a, P. Richerme a, D. Grzonka b, W. Oelert b, T. Sefzick b, M. Zielinski b, J.S. Borbely c, M.C. George c, E.A. Hessels c, C.H. Storry c, M. Weel c, A. M ullers¨ d, J. Walz d, A. Speck e a Department of Physics, Harvard University, Cambridge, MA 02138, United States b IKP, Forschungszentrum Julich¨ GmbH, 52425 Julich,¨ Germany c York University, Department of Physics and Astronomy, Toronto, Ontario, Canada M3J 1P3 d Institut fur¨ Physik, Johannes Gutenberg Universit at,¨ D-55099 Mainz, Germany e Rowland Institute at Harvard, Harvard University, Cambridge, MA 02142, United States article info abstract Article history: Extremely precise tests of fundamental particle symmetries should be possible via laser spectroscopy of Received 24 August 2010 trapped antihydrogen (H) atoms. H atoms that can be trapped must have an energy in temperature Received in revised form units that is below 0.5 K —the energy depth of the deepest magnetic traps that can currently be 4 January 2011 constructed with high currents and superconducting technology. The number of atoms in a Boltzmann Accepted 11 January 2011 distribution with energies lower than this trap depth depends sharply upon the temperature of the Available online 21 January 2011 thermal distribution.
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