[Previous] | [Session 32] | [Next]
E. Grün (MPI-K and HIGP), R. Srama, M. Rachev, A. Srowig (MPI-K), D. Harris, T. Conlon (HIGP), S. Auer (A&M Assoc.)
A dust telescope is a combination of a dust trajectory sensor together with an analyzer for the chemical composition of dust particles in space. Dust particles' trajectories are determined by the measurement of the electric signals that are induced when a charged grain flies through a position sensitive electrode system. The objective of the trajectory sensor is to measure dust charges in the range 10-16 to 10-13 C and dust speeds in the range 6 to 100 km/s. The trajectory sensor has four sensor planes consisting of about 20 wire electrodes each. Two adjacent planes have orthogonal wire direction. The distance between planes is about 40 mm and the distance between electrodes in one plane is about 20 mm. A 40 cm long wire electrode in such an array has approx. 6 pF capacitance. The expected noise on each electrode is about 3 10-17 C. The signal on each electrode is sampled at 25 MHz rate.
The dust chemical analyzers will have a sufficient mass resolution in order to resolve ions with atomic mass number up to 100. The impact area of the mass analyzer will be 0.1 m2. We have constructed a numerical model of the mass spectrometer consisting of the target area with acceleration grid and the two-stage reflectron consisting of three grids, and the central ion detector. Ions of varying starting positions at the target, emission angles and energies are flown through the spectrometer. A first result is that ions with different perpendicular (to the target normal) energies will arrive at the ion detector at different radial positions, with zero perpendicular energy in the center. Since the flight path and time of these ions varies accordingly an ion detector made of several detectors arranged in concentric rings will provide improved resolution.
If the author provided an email address or URL for general inquiries,
it is as follows:
Bulletin of the American Astronomical Society, 34, #3< br> © 2002. The American Astronomical Soceity.