A TRANSIT-TIME ANALYZER FOR DETERMINING THE ELEMENTAL COMPOSITION OF COSMIC DUST

A transit-time analyzer for investigating high-speed microparticles is described. It was designed to determine the elemental composition of cosmic dust. A small source of ions, the ionization being by high-ener gy fission fragments of 252Cf, is suggested as a facility for the auto nomous testing of the analyzer on board a spacecraft. The range of ion masses detected by the analyzer is M = 1-500 amu, the resolution is R 10% = 170 for M = 120 amu; the speed of analyzer microparticles is v g reater than or similar to 1 km/sec; their mass is m = 10(-10)-10(-15)g . The target area of the analyzer(similar to 200 cm(2)) yields a detec tion rate of similar to 7.10(-2) particle/h when the flux density is s imilar to 10(-3)m(-2) sec(-1), which is typical around the earth.