Medium-Energy Particle Experiments - Ion Mass Analyzer, MEP-i


Measurement Principle

The electrostatic analyzer measures the energy per charge and direction of incoming ions. The mass per charge is determined by time-of-flight (TOF) analysis. The charge is obtained by measuring the ion energy with solid state detectors (SSDs).


Shoichiro Yokota (Osaka University)
Satoshi Kasahara (The University of Tokyo)

Instrument Specifications

  • Energy range: <10 to 180 keV/q
  • Energy resolution: 7% (FWHM)
  • Energy steps: 16 steps per scan
  • Mass discrimination: H+, He++, He+, O+, O+2
  • Sensor field of view: 360° (azimuth) × 3.5° (elevation)
  • Number of anodes: 16
  • Geometric factor
    • 2.4×10-4 cm2 sr keV/keV/anode (normal)
    • 1.9×10-5 cm2 sr keV/keV/anode (narrow)
  • Time resolution: 4 s for full 3-D distribution function