Low-Energy Particle Experiments - Electron Analyzer; LEP-e


Measurement Principle

Low-Energy Particle Experiments - Electron Analyzer (LEPe) onboard the ERG spacecraft measures three-dimensional distribution functions of low energy electrons. The LEPe instrument consists of a tophat-type electrostatic analyzer, multi-channel plates (MCP), high-voltage power supplies and power supply units. The analyzer selects energies of electrons from ~19 eV to 19 keV in 32 energy steps. LEPe has a fan-shaped field of views, which changes its direction by spin motion to measure in 16 spin-phase directions.


Principal Investigator
Paul Ho (Academia Sinica, Taiwan)
Project Manager
Shiang-Yu Wang (Academia Sinica, Taiwan)
Project Scientist
Sunny W. Y. Tam (National Cheng Kung University, Taiwan)
Project Engineer
Yoichi Kazama (Academia Sinica, Taiwan)
Bo-Jhou Wang (Academia Sinica, Taiwan)
Support Scientist
Tzu-Fang Chang (National Cheng Kung University, Taiwan)
Chih-Yu Chiang (National Cheng Kung University, Taiwan)

Instrument Specifications

Parameter Unit Remark
upper part 180DIA x 200H mm
lower part 170D x 180W x 90H mm
Mass 5.512 kg
Power consumption 8.8 W 44V*0.20A, incl. PSU’s efficiency
Raw data production 24.6 kbyte/spin Science data, w/o compression
G-factor w/o mesh
Coarse ch 9.34e-4 cm2 sr keV/keV Average, measured
Fine ch 2.15e-4 cm2 sr keV/keV Average, measured
Energy range ~19 - 19,000 eV @4kV HV
Energy resolution 9.2 % FWHM, measured
Field of views 2.98 x ~270 deg Science data, w/o compression
Angular resolution
Coarse ch 2.89 x 21.5 deg EL x AZ, FWHM, measured
Fine ch 3.05 x 4.71 deg EL x AZ, FWHM, measured