Abstract: A probe and method for using the same for supporting a sample in an ion source of a mass spectrometer comprises a target formed by a receptacle for a liquid sample in which the sample passes by diffusion to the high vacuum side of a semipermeable membrane and/or in which the sample is held as a droplet by surface tension. In order to replenish the droplet surface, the supply can be arranged to overflow the receptacle.

Abstract: A charged particle energy analyzer, such as a microscope or spectrometer, includes a magnetic immersion lens 10 to focus charged particles emitted from an irradiated specimen 5 located within the magnetic field of the lens. A collecting aperture 18 defines the area of the irradiated specimen from which charged particles can be brought to a focus in the image plane of the lens but an aperture 21 in this plane selects and defines a much smaller area of the specimen from which the received particles are passed to a suitable energy analyzing means 25. The energy analyzing means 25 then performs energy analysis of the small selected area of the specimen by imaging the small area with emitted particles of a predetermined energy, or energy scanning the particles emitted from this area, so giving a chemical analysis of the small selected area of the specimen surface.