Van Allen Probe B ECT HOPE Spin Resolved Level 2 Science Data

As a mass spectrometer instrument, HOPE uses an electrostatic top-hat analyzer and time-gated coincidence detectors to measure electrons, protons, and helium and oxygen ions with energies from less than or equal to 20 eV or spacecraft potential (whichever is greater) to greater than or equal to 45 keV while rejecting penetrating backgrounds.

Spectral measurements for both ions and electrons are acquired over 1 eV to 50 keV in 36 log-spaced steps at an energy resolution ΔEFWHM/E ~15%. The dominant ion species (H+, He+, and O+) of the magnetosphere are identified using foil-based time-of-flight mass (TOF) spectrometry with channel electron multiplier (CEM) detectors. Angular measurements are derived using five polar pixels in a plane perpendicular to the spacecraft spin axis, and up to 16 azimuthal bins are acquired for each polar pixel over time as the spacecraft spins.