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Ahrens et al. 2003
Ahrens, T.J., Gupta, S.C., Jyoti, G. and Beauchamp, J.L. (2003). Mass spectrometer calibration of Cosmic Dust Analyzer. Journal of Geophysical Research 108. doi: 10.1029/2002JE001912. issn: 0148-0227.

The time-of-flight (TOF) mass spectrometer (MS) of the Cosmic Dust Analyzer (CDA) instrument aboard the Cassini spacecraft is expected to be placed in orbit about Saturn to sample submicrometer-diameter ring particles and impact ejecta from Saturn's satellites. The CDA measures a mass spectrum of each particle that impacts the chemical analyzer sector of the instrument. Particles impact a Rh target plate at velocities of 1-100 km/s and produce some 10-8 to 10-5 times the particle mass of positive valence, single-charged ions. These are analyzed via a TOF MS. Initial tests employed a pulsed N2 laser acting on samples of kamacite, pyrrhotite, serpentine, olivine, and Murchison meteorite induced bursts of ions which were detected with a microchannel plate and a charge sensitive amplifier (CSA). Pulses from the N2 laser (1011 W/cm2) are assumed to simulate particle impact. Using aluminum alloy as a test sample, each pulse produces a charge of ~4.6 pC (mostly Al+1), whereas irradiation of a stainless steel target produces a ~2.8 pC (Fe+1) charge. Thus the present system yields ~10-5% of the laser energy in resulting ions. A CSA signal indicates that at the position of the microchannel plate, the ion detector geometry is such that some 5% of the laser-induced ions are collected in the CDA geometry. Employing a multichannel plate detector in this MS yields for Al-Mg-Cu alloy and kamacite targets well-defined peaks at 24 (Mg+1), 27(Al+1), and 64 (Cu+1) and 56 (Fe+1), 58 (Ni+1), and 60 (Ni+1) dalton, respectively.

BACKGROUND DATA FILES

Abstract

Keywords
Interplanetary Physics, Interplanetary dust, Mineral Physics, Shock wave experiments, Planetary Sciences, Impact phenomena (includes cratering), Planetary Sciences, Rings and dust, Planetology, Comets and Small Bodies, Dust
Journal
Journal of Geophysical Research
http://www.agu.org/journals/jb/
Publisher
American Geophysical Union
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