The Akebono Suprathermal Mass Spectrometer (SMS)
is a radio-frequency ion mass spectrometer. It is designed to measure
the mass composition and velocity distribution (mass-per-charge,
energy-per-charge and angular distribution in the spacecraft
spin-plane) of thermal and suprathermal (0.1-4000 eV/q) ions in the
ionosphere and magnetosphere. It consists of a retarding potential
analyzer, a 3-stage modified Bennett ion mass spectrometer, and a
micro-channel plate detector. It can sample ions at 256 mass steps
over the 1-80 AMU/q mass range, and 256 retarding potential steps
in the 0.1-25.6V range, and 16 suprathermal energy steps in the
100-4000 V range. It operates in a number of fast scan and mass
scan operational modes.
For a detailed description of the SMS instrument and its operation,
please see B. A. Whalen, J. R. Burrows, A. W. Yau, E. E. Budzinski,
A. M. Pilon, I. Iwamoto, K. Marubashi, S. Watanabe, H. Mori, and
E. Sagawa, The suprathermal ion mass spectrometer (SMS) onboard
the EXOS?D satellite. J. Geomag. Geoelectr. 42, 511-536, 1990 and
A. W. Yau, E. Drakou, M. J. Greffen, D. J. Knudsen, and E. Sagawa,
Radio-frequency ion mass spectrometer measurements of thermal ion
composition, velocity, and temperature: the EXOS-D Suprathermal
Mass Spectrometer, Geophys. Monogr. Ser., 102, 307-312, 1998. See also
http://www.darts.isas.jaxa.jp/akbn/readme/readme.sms.txt