The Relativistic Electron-Proton Telescope (REPT) Instrument on Board the Radiation Belt Storm Probes (RBSP) Spacecraft: Characterization of Earth’s Radiation Belt High-Energy Particle Populations

Particle acceleration and loss in the million electron Volt (MeV) energy range (and above) is the least understood aspect of radiation belt science. In order to measure cleanly and separately both the energetic electron and energetic proton components, there is a need for a carefully designed detector system. The Relativistic Electron-Proton Telescope (REPT) on board the Radiation Belt Storm Probe (RBSP) pair of spacecraft consists of a stack of high-performance silicon solid-state detectors in a telescope configuration, a collimation aperture, and a thick case surrounding the detector stack to shield the sensors from penetrating radiation and bremsstrahlung. The instrument points perpendicular to the spin axis of the spacecraft and measures high-energy electrons (up to ∼20 MeV) with excellent sensitivity and also measures magnetospheric and solar protons to energies well above E=100 MeV. The instrument has a large geometric factor (g=0.2 cm2 sr) to get reasonable count rates (above background) at the higher energies and yet will not saturate at the lower energy ranges. There must be fast enough electronics to avert undue dead-time limitations and chance coincidence effects. The key goal for the REPT design is to measure the directional electron intensities (in the range 10−2–106 particles/cm2 s sr MeV) and energy spectra (ΔE/E∼25 %) throughout the slot and outer radiation belt region. Present simulations and detailed laboratory calibrations show that an excellent design has been attained for the RBSP needs. We describe the engineering design, operational approaches, science objectives, and planned data products for REPT.

[1]  Daniel N. Baker,et al.  Linear prediction filter analysis of relativistic electron properties at 6.6 RE , 1990 .

[2]  Umran S. Inan,et al.  Wave acceleration of electrons in the Van Allen radiation belts , 2005, Nature.

[3]  P. Pani,et al.  GEMS: Underwater spectrometer for long-term radioactivity measurements , 2011 .

[4]  K. R. Lorentzen,et al.  Multisatellite observations of MeV ion injections during storms , 2002 .

[5]  D. Baker,et al.  Energetic Electrons in the Magnetosphere of Jupiter , 1974, Science.

[6]  Jörg Büchner,et al.  Space Plasma Simulation , 2003 .

[7]  M. Johnson,et al.  Combined Release and Radiation Effects Satellite (CRRES): Spacecraft and Mission , 1992 .

[8]  D. Baker,et al.  Low‐altitude measurements of 2–6 MeV electron trapping lifetimes at 1.5 ≤ L ≤ 2.5 , 2007 .

[9]  E. Grigoriev,et al.  STUDY OF CHARGE TRANSPORT IN NON-IRRADIATED AND IRRADIATED SILICON DETECTORS , 1999 .

[10]  D. Baker,et al.  A strong CME‐related magnetic cloud interaction with the Earth's Magnetosphere: ISTP observations of rapid relativistic electron acceleration on May 15, 1997 , 1998 .

[11]  J. Raeder Global Magnetohydrodynamics — A Tutorial , 2003 .

[12]  George C. Ho,et al.  Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) , 2013, Space Science Reviews.

[13]  Richard M. Thorne,et al.  Potential waves for relativistic electron scattering and stochastic acceleration during magnetic storms , 1998 .

[14]  R. Horne,et al.  Evidence for chorus‐driven electron acceleration to relativistic energies from a survey of geomagnetically disturbed periods , 2003 .

[15]  Scot R. Elkington,et al.  Resonant acceleration and diffusion of outer zone electrons in an asymmetric geomagnetic field , 2003 .

[16]  David G. Sibeck,et al.  Science Objectives and Rationale for the Radiation Belt Storm Probes Mission , 2012, Space Science Reviews.

[17]  R. A. Mewaldt,et al.  Solar Energetic Particle Composition, Energy Spectra, and Space Weather , 2007 .

[18]  Daniel N. Baker,et al.  PET: a proton/electron telescope for studies of magnetospheric, solar, and galactic particles , 1993, IEEE Trans. Geosci. Remote. Sens..

[19]  W. Kolasinski,et al.  Injection of electrons and protons with energies of tens of MeV into L < 3 on 24 March 1991. (Reannouncement with new availability information) , 1992 .

[20]  D. Baker,et al.  Highly relativistic magnetospheric electrons: A role in coupling to the middle atmosphere? , 1987 .

[21]  D. Baker,et al.  Physical models of the geospace radiation environment , 2004 .

[22]  M. Dunlop,et al.  Multisatellite measurements of electron phase space density gradients in the Earth's inner and outer magnetosphere , 2004 .

[23]  J. B. Blake,et al.  Relativistic Electron Acceleration and Decay Time Scales in the Inner and Outer Radiation Belts: SAMPEX , 1994 .

[24]  E. W. Hones,et al.  LOS Alamos geostationary orbit synoptic data set: A compilation of energetic particle data , 1981 .

[25]  V. Angelopoulos,et al.  An Observation Linking the Origin of Plasmaspheric Hiss to Discrete Chorus Emissions , 2009, Science.

[26]  J. B. Blake,et al.  Effects of the solar wind on magnetospheric dynamics: Energetic electrons at the synchronous orbit , 2013 .

[27]  C. Russell The Global Geospace Mission , 1995 .

[28]  Xinlin Li,et al.  Modeling energetic particle injections in dynamic pulse fields with varying propagation speeds , 2002 .

[29]  C. Ammerlaan,et al.  Particle identification by pulse shape discrimination in the p-i-n type semiconductor detector , 1963 .

[30]  Richard M. Thorne,et al.  Evolution of energetic electron pitch angle distributions during storm time electron acceleration to megaelectronvolt energies , 2003 .

[31]  Joseph E. Borovsky,et al.  Measurement techniques in space plasmas : particles , 1998 .

[32]  D. Baker,et al.  Injection of Energetic Ions During the 31 March 0630 Substorm , 2013 .

[33]  D. D. Zeeuw,et al.  Semirelativistic Magnetohydrodynamics and Physics-Based Convergence Acceleration , 2002 .

[34]  James I. Vette,et al.  The NASA/National Space Science Data Center trapped radiation environment model program, 1964 - 1991 , 1991 .

[35]  Jean-Francois Beche,et al.  Second order Pseudo-gaussian shaper , 2002 .

[36]  P. Morokhov,et al.  Selection of the Shaping Circuits of a Multilayer Semiconductor Spectrometer of Charged Particles , 2002 .

[37]  D. Baker,et al.  Long term measurements of radiation belts by SAMPEX and their variations , 2001 .

[38]  Scot R. Elkington,et al.  Acceleration of relativistic electrons via drift‐resonant interaction with toroidal‐mode Pc‐5 ULF oscillations , 1999 .

[39]  M. Kivelson,et al.  Relativistic electrons in the outer radiation belt: Differentiating between acceleration mechanisms , 2004 .

[40]  W. P. Olson Quantitative modeling of magnetospheric processes , 1979 .

[41]  Juan G. Roederer,et al.  Dynamics of Geomagnetically Trapped Radiation , 1970 .

[42]  D. Baker,et al.  Magnetospheric response to magnetic cloud (coronal mass ejection) events : Relativistic electron observations from SAMPEX and Polar , 1999 .

[43]  John Lyon,et al.  The Lyon-Fedder-Mobarry (LFM) global MHD magnetospheric simulation code , 2004 .

[44]  Richard M. Thorne,et al.  Outward radial diffusion driven by losses at magnetopause , 2006 .

[45]  D. Baker,et al.  Physical mechanisms of compressional EMIC wave growth , 2010 .

[46]  C. Mosher Pseudo-Gaussian Transfer Functions with Superlative Baseline Recovery , 1976, IEEE Transactions on Nuclear Science.

[47]  E. W. Hones,et al.  Do Jovian electrons influence the terrestrial outer radiation zone , 1979 .

[48]  Daniel N. Baker,et al.  An overview of the Solar Anomalous, and Magnetospheric Particle Explorer (SAMPEX) mission , 1993, IEEE Trans. Geosci. Remote. Sens..

[49]  D. Baker,et al.  An extreme distortion of the Van Allen belt arising from the ‘Hallowe'en’ solar storm in 2003 , 2004, Nature.

[50]  T. O'Brien,et al.  The Relativistic Proton Spectrometer (RPS) for the Radiation Belt Storm Probes Mission , 2013 .

[51]  D. Crawford,et al.  The Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) on RBSP , 2013 .

[52]  F. S. Goulding,et al.  Ballistic deficits in pulse shaping amplifiers , 1987 .

[53]  Richard M. Thorne,et al.  Timescale for radiation belt electron acceleration by whistler mode chorus waves , 2005 .

[54]  M. Hudson,et al.  Resonant enhancement of relativistic electron fluxes during geomagnetically active periods , 1999 .

[55]  A. Vampola Measuring Energetic Electrons — What Works and What Doesn't , 2013 .

[56]  T. Pulkkinen,et al.  The inner magnetosphere : physics and modeling , 2005 .

[57]  D. Baker,et al.  Simulation of dispersionless injections and drift echoes of energetic electrons associated with substorms , 1998 .

[58]  Daniel N. Baker,et al.  Quantitative prediction of radiation belt electrons at geostationary orbit based on solar wind measurements , 2001 .