Skip to main content

Table 1 MEP-i performance and specifications

From: Medium-energy particle experiments–ion mass analyzer (MEP-i) onboard ERG (Arase)

Parameter Value Notes
Energy range 10–180 keV/q  
Energy resolution 7% FWHM
37% SV step interval
Analyzer constant 18  
Number of energy steps 16 per spin The first-step data were not used for scientific analyses due to the slow ramping of SV
Mass discrimination H+, He++, He+, O++, O+ and O2 +  
FOV 360° (azimuth) × 2.7° (elevation) Azimuthal gaps between detectors
10.5° (azimuth) × 2.7° (elevation) per anode FWHM
Number of anodes 16 Circularly arrayed
Geometric factor of ESA 2.9 × 10−4 cm2 sr eV/eV per anode (normal channel) Calculated in the numerical model
6.0 × 10−5 cm2 sr eV/eV per anode (narrow channel) Calculated in the numerical model
Time resolution 4 s per full 3-D distribution function
500 ms per energy sweep (16 steps)
31.3 ms per energy step
For normal spin of 8 s
Sensor size ϕ310 mm × 402 mm Including an electronics box for the CPU and power supply unit (PSU)
Sensor mass 9.8 kg  
Power consumption 23 W The efficiency of PSU is 60%
Data size 6.556 kBytes per energy sweep Before compression and reduction
  1. The resolution is indicated by the full-width at half maximum (FWHM)