Analysis of solid chemical and biological particles is achieved by a miniature mass spectrometer and apparatus attached thereto for vaporizing or ablating a stream of chemical and biological particles by a pulsed laser and/or pyrolysis heater sub-assembly at atmospheric pressure or, when desirable, in a vacuum. The mass spectrometer includes a collimation chamber, a repeller assembly, an internal ionization chamber, a mass filter and ion separation chamber, a drift space region, and a multi-channel ion detection array so as to permit the collection and analysis of ions formed over a wide mass range simultaneously. The apparatus for vaporizing or ablating includes an output port adjacent the input to the collimation and vaporization chamber so as to maximize the amount of vaporized material being fed into the mass spectrometer.