Space Science Reviews

, Volume 146, Issue 1, pp 117–147

The IBEX-Lo Sensor

  • S. A. Fuselier
  • P. Bochsler
  • D. Chornay
  • G. Clark
  • G. B. Crew
  • G. Dunn
  • S. Ellis
  • T. Friedmann
  • H. O. Funsten
  • A. G. Ghielmetti
  • J. Googins
  • M. S. Granoff
  • J. W. Hamilton
  • J. Hanley
  • D. Heirtzler
  • E. Hertzberg
  • D. Isaac
  • B. King
  • U. Knauss
  • H. Kucharek
  • F. Kudirka
  • S. Livi
  • J. Lobell
  • S. Longworth
  • K. Mashburn
  • D. J. McComas
  • E. Möbius
  • A. S. Moore
  • T. E. Moore
  • R. J. Nemanich
  • J. Nolin
  • M. O’Neal
  • D. Piazza
  • L. Peterson
  • S. E. Pope
  • P. Rosmarynowski
  • L. A. Saul
  • J. R. Scherrer
  • J. A. Scheer
  • C. Schlemm
  • N. A. Schwadron
  • C. Tillier
  • S. Turco
  • J. Tyler
  • M. Vosbury
  • M. Wieser
  • P. Wurz
  • S. Zaffke
Article

DOI: 10.1007/s11214-009-9495-8

Cite this article as:
Fuselier, S.A., Bochsler, P., Chornay, D. et al. Space Sci Rev (2009) 146: 117. doi:10.1007/s11214-009-9495-8

Abstract

The IBEX-Lo sensor covers the low-energy heliospheric neutral atom spectrum from 0.01 to 2 keV. It shares significant energy overlap and an overall design philosophy with the IBEX-Hi sensor. Both sensors are large geometric factor, single pixel cameras that maximize the relatively weak heliospheric neutral signal while effectively eliminating ion, electron, and UV background sources. The IBEX-Lo sensor is divided into four major subsystems. The entrance subsystem includes an annular collimator that collimates neutrals to approximately 7°×7° in three 90° sectors and approximately 3.5°×3.5° in the fourth 90° sector (called the high angular resolution sector). A fraction of the interstellar neutrals and heliospheric neutrals that pass through the collimator are converted to negative ions in the ENA to ion conversion subsystem. The neutrals are converted on a high yield, inert, diamond-like carbon conversion surface. Negative ions from the conversion surface are accelerated into an electrostatic analyzer (ESA), which sets the energy passband for the sensor. Finally, negative ions exit the ESA, are post-accelerated to 16 kV, and then are analyzed in a time-of-flight (TOF) mass spectrometer. This triple-coincidence, TOF subsystem effectively rejects random background while maintaining high detection efficiency for negative ions. Mass analysis distinguishes heliospheric hydrogen from interstellar helium and oxygen. In normal sensor operations, eight energy steps are sampled on a 2-spin per energy step cadence so that the full energy range is covered in 16 spacecraft spins. Each year in the spring and fall, the sensor is operated in a special interstellar oxygen and helium mode during part of the spacecraft spin. In the spring, this mode includes electrostatic shutoff of the low resolution (7°×7°) quadrants of the collimator so that the interstellar neutrals are detected with 3.5°×3.5° angular resolution. These high angular resolution data are combined with star positions determined from a dedicated star sensor to measure the relative flow difference between filtered and unfiltered interstellar oxygen. At the end of 6 months of operation, full sky maps of heliospheric neutral hydrogen from 0.01 to 2 keV in 8 energy steps are accumulated. These data, similar sky maps from IBEX-Hi, and the first observations of interstellar neutral oxygen will answer the four key science questions of the IBEX mission.

Keywords

Neutral atom imagingHeliosphereTermination shockEnergetic neutral atomsMagnetosphereSurface ionization

Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  • S. A. Fuselier
    • 1
  • P. Bochsler
    • 3
  • D. Chornay
    • 5
  • G. Clark
    • 2
  • G. B. Crew
    • 13
  • G. Dunn
    • 4
  • S. Ellis
    • 2
  • T. Friedmann
    • 10
  • H. O. Funsten
    • 9
  • A. G. Ghielmetti
    • 1
  • J. Googins
    • 2
  • M. S. Granoff
    • 2
  • J. W. Hamilton
    • 1
  • J. Hanley
    • 4
  • D. Heirtzler
    • 2
  • E. Hertzberg
    • 1
  • D. Isaac
    • 1
  • B. King
    • 2
  • U. Knauss
    • 2
  • H. Kucharek
    • 2
  • F. Kudirka
    • 2
  • S. Livi
    • 2
  • J. Lobell
    • 5
  • S. Longworth
    • 2
  • K. Mashburn
    • 8
  • D. J. McComas
    • 4
  • E. Möbius
    • 2
  • A. S. Moore
    • 1
  • T. E. Moore
    • 5
  • R. J. Nemanich
    • 11
  • J. Nolin
    • 2
  • M. O’Neal
    • 2
  • D. Piazza
    • 3
  • L. Peterson
    • 2
  • S. E. Pope
    • 4
  • P. Rosmarynowski
    • 5
  • L. A. Saul
    • 3
  • J. R. Scherrer
    • 4
  • J. A. Scheer
    • 3
  • C. Schlemm
    • 7
  • N. A. Schwadron
    • 12
  • C. Tillier
    • 1
  • S. Turco
    • 2
  • J. Tyler
    • 2
  • M. Vosbury
    • 2
  • M. Wieser
    • 6
  • P. Wurz
    • 3
  • S. Zaffke
    • 2
  1. 1.Lockheed Martin Advanced Technology CenterPalo AltoUSA
  2. 2.University of New HampshireDurhamUSA
  3. 3.Physikalisches InstitutUniversity of BernBernSwitzerland
  4. 4.Southwest Research InstituteSan AntonioUSA
  5. 5.Goddard Space Flight CenterGreenbeltUSA
  6. 6.Swedish Institute of Space PhysicsKirunaSweden
  7. 7.Applied Physics LaboratoryJohns Hopkins UniversityLaurelUSA
  8. 8.Montana State UniversityBozemanUSA
  9. 9.ISR Division MS B241Los Alamos National LaboratoryLos AlamosUSA
  10. 10.Sandia Laboratory, Mail Stop 1415AlbuquerqueUSA
  11. 11.University of ArizonaTusconUSA
  12. 12.Boston UniversityBostonUSA
  13. 13.MIT Kavli Institute for Astrophysics and Space ResearchCambridgeUSA