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Table 1 Specification and performance of LEPi

From: Low-energy particle experiments–ion mass analyzer (LEPi) onboard the ERG (Arase) satellite

Parameter Value Unit Notes
Energy range < 0.01–25 keV/q  
Energy resolution 0.16 @ 0.01 keV/q   \(\Delta E / E\)
0.13 @ 12 keV/q   \(\Delta E / E\)
Analyzer constant 5.0   
Inner dome radius 41.5 mm Electrode in ESA
Outer dome radius 45.5 mm Electrode in ESA
Mass discrimination \(\hbox {H}^{+}\), \(\hbox {H}_{2}^{+}\)/\(\hbox {He}^{++}\), \(\hbox {He}^{+}\)   
\(\hbox {N}^{++}\)/\(\hbox {O}^{++}\), \(\hbox {N}^{+}\)/\(\hbox {O}^{+}\)   
\(\hbox {N}_{2}^{+}\)/\(\hbox {NO}^{+}\)/\(\hbox {O}_{2}^{+}\)   
Post-acceleration potential − 4.9 kV Foil potential
Length of TOF drift path 26 mm  
FOV 310 \(\times\) 4.5 deg × deg FWHM
Angle response of azimuthal channels 16.0 deg FWHM, wide channel
4.3 deg FWHM, narrow channel
Separation of azimuthal channels 22.5 deg  
Geometric factor 1.7 @ 0.01 keV/q 10\(^{-3}\) \(\hbox {cm}^{2}\) str keV/keV/channel Wide channel
1.4 @ 12 keV/q 10\(^{-3}\) \(\hbox {cm}^{2}\) str keV/keV/channel Wide channel
0.40 @ 0.01 keV/q 10\(^{-3}\) \(\hbox {cm}^{2}\) str keV/keV/channel Narrow channel
0.32 @ 12 keV/q 10\(^{-3}\) \(\hbox {cm}^{2}\) str keV/keV/channel Narrow channel
Number of energy steps 32   
Number of mass bins 1–8   Normal mode, commandable
1–509   TOF mode, commandable
Number of azimuthal bins 1–15   Normal mode, commandable
1   TOF mode
Number of spin phase bins 1–16   Normal mode, commandable
1–4   TOF mode, commandable
Time resolution 1–65,536 Satellite spin (nominal spin period: 8 s) Full 3D observation both for normal and TOF modes commandable
Dead time 1 ms/energy step Commandable
Sensor size 235 \(\times\) 235 \(\times\) 362 mm \(\times\) mm \(\times\) mm  
Sensor mass 6.94 kg  
Power consumption 23.8 W Primary side