Performance of the Gravity Probe B Cryogenic Sub-System

POSTER

Abstract

The experimental design of Gravity Probe B was based substantially on low temperature technology. In addition to the thermal environment provided by the 2400-liter, 1.8 K super-fluid He dewar, the cryogenic sub-system was responsible for controlling the mechanical, magnetic, vacuum, and optical environments of the Science Instrument Assembly (SIA). A highly stable sub-nT magnetic field region for the SIA is required to limit trapped flux in the superconducting gyro rotors to $<$ 0.9 nT (uniform field equivalent) and to attenuate external field by 240 dB. The magnetic field requirements were satisfied in part by use of an expanded superconducting lead-foil shield installed into the dewar prior to the integration of the cryostat probe housing the SIA. This required that the shield be continuously kept below its transition temperature (7 K) to the end of the science mission, including during integration of a warm probe with the cold dewar. Additional key requirements and the design of the cryogenic sub-system are also described in this poster as well as key flight results including trapped flux in the gyro rotors (0.3 nT uniform field equivalent), and cryogen lifetime (17.3 months).

Authors

  • Michael Taber

    Stanford University

  • Gerald Gabrielse

    Oak Ridge National Laboratory, Michigan State University, University of Maryland, Colorado School of Mines, ORAU, Tennessee Tech., University of Tennessee, ORNL, Rutgers University, Surrey, Rutgers, IFJ PAN Krakow, Rutgers, CSM, U. Tenn., Ohio U., Tenn. Tech. U., Tenn. Tech., Oak Ridge Assoc. U., Col. School of Mines, UNC - Chapel Hill, U. of Tenn., Oak Ridge Nat. Lab., Labratori Nazionali del Sud-INFN, Catania, Italy, Cyclotron Institute, Texas A\&M University, Dept. of Physics, Florida State University, U. North Carolina, Universidad de Buenos Aires, University of Texas, Lancaster University, Northwestern University, University of California, Riverside, Indiana University, Helmholtz Inst., Univ. Bonn, D-53115 Bonn, Forschungszentrum Juelich, IKP, D-52425 Juelich, Univ. of Michigan, Ann Arbor, MI 48109-1120, Department of Physics and Astronomy, Ursinus College, Pennsylvania, National Superconducting Cyclotron Laboratory, Michigan State University, Michigan, National Superconducting Cyclotron Laboratory at Michigan State University, Univ of Oslo, Mississippi St Univ, Univ. of Massachusetts-Lowell, Niels Bohr Institute, Univ of Tennessee, Argonne National Lab, Florida St Univ, US Naval Academy, A.F. Ioffe Phys. Techn. Inst., 198904 St. Petersburg, Russia, IKP, 52425 Julich, Germany; iThemba Labs, South Africa, JIHIR, Univ. of Tennessee, UNIRIB, Oak Ridge National Laboratory (supported by U.S. DOE contract \# DE-AC05-00OR22725), University of Edinburgh, Argonne National Laboratory, Department of Physics and Astronomy and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824, Department of Chemistry, and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, Department of Chemistry, Michigan State University, East Lansing, MI 48824, Forschungszentrum Julich, IUSB, Hope College, Concordia College, NSCL/MSU, FSU, INP, Rez, Czech republic, Texas A\&M University, Yale University, University of North Carolina, Kyushu University, Japan, Michigan State University, USA, RCNP, Osaka, Japan, WITS, University of South Africa, Osaka University, Japan, KVI, Groningen, The Netherlands, University of Notre Dame, USA, Imperial College, Radboud University Nijmegen, LPNHE, Paris Universities VI and VII, Freiburg University, University of Michigan, University of Washington, McGill University, Brown University, Boston University, LLNL, LBNL, NSCL, MSU, NSCL \& Dept. of Chemistry, MSU, East Lansing, Dept. of Physics, FSU, Tallahassee, NSCL/Michigan State University, The Australian National University, Australian National University, Washington University, Lund University, University of Kentucky, Colorado State University, Los Alamos National Laboratory, University of South Carolina, Lawrence Berkeley National Laboratory, MPA, Germany, LSU, AEI, Germany, University of Southampton, UK, Aristotle University of Thessaloniki, Greece, Department of Physics, Florida Atlantic University, Pennsylvania State University, Andrews University, Department of Physics, Olabisi Onabanjo University, PMB 2002, Ago - Iwoye, Nigeria, University of Rochester, University of Wisconsin-Madison, University of California, Berkeley and Lawrence Berkeley National Laboratory, Observatoire de Strasbourg, Ohio University, Anglo-Australian Observatory, Rajshahi University, Rajshahi, Bangladesh, University of Rajshahi, Rajshahi, Bangladesh, MIT, M.I.T., PPPL, University of Kansas, Div. of General Education, Namseoul University, Dept. of Advanced Materials, Sunmoon University, Dept. of Computer and Applied Physics, Hanseo University, Texas A\&M University, Commerce, TUNL, University of South Dakota, LANL, Florida State University, Fermi National Accelerator Laboratory, Columbia University, Defense Trade Controls Policy, U.S. Department of State, Deutsches Elektronen-Synchrotron, Hamburg, Germany, Case Western Reserve University, American Physical Society and City College of New York, Dipartimento di Scienze Fisiche, Universita Federico II, Napoli and INFN, Napoli, Italy, Experimentalphysik III, Ruhr Universit\&#034;at Bochum, Germany, University of Connecticut, Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH), Romania, Fakult\&#034;at f\&#034;ur Physik und Astronomie, Ruhr Universit\&#034;at Bochum, Germany, Chinese Institute of Atomic Energy, Beijing, China, Experimentalphysik III, Ruhr Universit\&#034;{a}t Bochum, Germany, U. of Kostanz, McMaster U., Simon Fraser U., TRIUMF, University of Notre Dame, Yale, York, IFIN-HH, Bucharest, Romania, Department of Physics, University of North Texas, Denton, Tx 76203, Depertment of Chemistry and Biochemistry, 607 Charles E Young Dr, UCLA, Los Angeles, Ca 90095, CBH Technologies, 4727 Wilshire Blvd, Los Angeles, Ca 90010, Iowa State University, UCLA, Washington Univ., Iowa State Univ., National Knowledge Commission of India, Centre for Policy Research, Lawrence Livermore National Laboratory, Stanford University, Lockheed-Martin Corp, NVI, Inc./NASA GSFC, Harvard-Smithsonian CfA, York University, Observatoire de Paris, Erskine College, KTH, Royal Institute of Technology, NIKHEF, State University of New York, Stony Brook, University of Florida, Harvard University, UC San Diego, Northwest Analysis, Apache Point Observatory, Humboldt State University, Purdue University, Saint Joseph&#039;s College, University of Aarhus, Denmark, M. I. T., Department of Physics, University of North Carolina at Charlotte, Polish Academy of Sciences, Mississippi State University, IEP Warsaw University, IFGA, University of Milan and INFN, Vanderbilt University, Louisianna State, Warsaw University, UNIRIB/ORAU, U. of Tennessee, Mississippi State, Florida State Unversity, Flordia State University, The University of Surrey, Ivan Allen College, Georgia Institute of Technology, NPR Radio, Temple U/JLAB, U Saskatchewan, U Cyprus, U Virginia, Canadian Light Source, LPSC Grenoble, University of Texas at Dallas, The Ohio State University, INFN Ferrara, University of Oregon, Bruy\`{e}res-le-Ch\^{a}tel, T.U.Munchen, Maryland University, Miss State University, Vanderbilt, University of Liverpool, Oak Ridge Associated Universities, Tennessee Tech University, University of Oslo, University of Massachusetts, The Niels Bohr Institute, U.S. Naval Academy, CCLRC Daresbury Laboratory, United States Naval Academy, Cornell University, JLAB, Johns Hopkins University, Royal Holloway University of London, University of California at Santa Cruz, University of Rome, La Sapienza, University of California at Irvine, University of Perugia, INFN Milano, INTEGRAL Science Data Centre, NASA/GSFC, MPE, Garching, Germany, Steward Observatory, Tucson, AZ, USA, Centre d&#039;Etude Spatiale des Rayonnements, Toulouse, France, Undersecretary for Science, Department of Energy, WNSL, Yale University, University of Surrey, UK and WNSL, Yale University, University of Paris VI and VII, Massachusetts Institute of Technology, Jefferson Lab, Thomas Jefferson National Accelerator Facility, Duke University, LLNL, Univ. of Notre Dame, Univ. of Notre Dame, Union College, Algarve University, National Science Foundation, California Institution of Technology, Director, Domestic Nuclear Detection Office, Transformational R\&D Directorate, Department of Homeland Security, NASA, IFGA - University of Milan and INFN, NCSU, VT, ISU, CEA-Saclay, DSM/DAPNIA/SPhN, NGCSU \& TUNL, Sandia National Lab, Duke U. \& TUNL, Fermilab, Harvard-Smithsonian Center for Astrophysics, ICRANet and Dipartimento di Fisica - Universit\`a di Roma ``La Sapienza&#039;&#039;, Ursinus College, Purdue University Calumet, GSI, Ohio Wesleyan University, University of Cincinnati, Universidad de Antioquia, ICRA and Dipartimento di Fisica - Universit\`a di Roma ``La Sapienza&#039;&#039;, Facolt\`a di Ingegneria, Universit\`a Campus Bio-Medico, and ICRA, Facolt\`a di Ingegneria, Universit\`a Campus Bio - Medico, Istituto per le Applicazioni del Calcolo ``M. Picone&#039;&#039;, CNR, and ICRA, JPL, Pasadena, CA, 91109, NASA/GSFC Greenbelt, MD 20771, Caltech, Pasadena, CA 91125, Washington University, St. Louis, MO 63130, The Pennsylvania State University