Abstract: The invention relates to a procedure for the analysis of surface and depth rofiles of partially or completely electrically non-conductive specimens using the direct bombardment method of the secondary neutral-particle mass spectrometry SNMS; to dissipate otherwise disturbing ion currents, it is being suggested that a high-frequency alternating voltage is applied to the underside of the specimen, the upperside of which is in contact with the low-pressure plasma used in the SNMS procedure, whereby the phase of this voltage is adjusted to such a time sequence that during the negative voltage part of the high-frequency period the specimen is bombarded by positive ions of a constant kinetic energy from the plasma and that the applied ion charge from the influx of plasma electrons is compensated during the positive part of the high-frequency period.

Abstract: An ionizable gas is accommodated in an ionization chamber having a first end and a second end which is spaced from the first end and is an outlet of the chamber. A first electrode is disposed at the first end and a second electrode in the form of a fine grating or grid is disposed at the second end. The electrodes are connected to a source of radio frequency current which is capable of establishing a potential difference of such magnitude between the electrodes as to ionize the gas. The gas is at a low pressure so that ionization of the gas produces a low-pressure plasma. The area of the first electrode is selected to be so much larger than the area of the second electrode that the magnitude of the voltage drop between the plasma and the first electrode is negligible compared to the voltage drop between the plasma and the second electrode. The positive ions resulting from ionization of the gas are accelerated towards the second electrode and travel through the same towrds an object to be bombarded.

Abstract: A high-frequency ion source for the production of an ion beam using electron cyclotron resonance has a tubular vessel whose shape matches the desired shape of the beam. The vessel, which is designed to accommodate an ionizable gas, is surrounded by a coil, and the coil is coupled to a high-frequency generator via a resonant circuit. A Helmholtz coil pair matched to the shape of the vessel is arranged to generate a magnetic field which is directed normal to the axis of the coil surrounding the vessel. The vessel is clamped between two plates and one of the plates contains a system for extracting ions from the vessel. The extraction system includes a plurality of spaced electrodes which function to attract and accelerate ions. The electrodes are formed with slotted openings which shape a stream of ions flowing out of the vessel into the form of a flat beam. An additional electrode can be provided to suppress the escape of electrons from the beam back into the vessel.

Abstract: An apparatus for the chemical analysis of a sample ejects neutral and charged particles from the sample by ion bombardment from a primary ion source. An electric diaphragm passes only the ejected neutral particles for ioniziation in a plasma which is separate from the primary ion source and which serves only for the post-ionization of the neutral particles. The ionized particles are then analyzed by mass spectrometry. Charging of insulating samples by primary ions is prevented by rendering the diaphragm permeable to plasma electrons.

Abstract: A system and method for removing material from the surface of a sample comprising: a high-frequency plasma produced in front of the sample surface; a metallic shield electrically insulated from the sample and provided with an opening determining the area to be removed, disposed between the sample and the high-frequency plasma. The parameters of this arrangement are chosen so that the relationU.sub.2 =(U.sub.1.sup.3/4 +D/C).sup.4/3with ##EQU1## holds, wherein: U.sub.2 =Potential difference applied between sample and plasma;D=spacing of sample surface from shield;.epsilon..sub.O =dielectric constant of vacuum;n=density of plasma;e.sub.o =elementary charge;k=Boltzmann constant;T.sub.e =electron temperature;p0 M.sub.i =atomic mass of the species of ions (plasma ions) used;m.sub.e =electron mass; and.pi.=3.14.