Process and apparatus for the mass spectrometric analysis of surfaces of solids

Claim 2

In a process for the analysis of surfaces of solids which comprises: a. generating a primary ion beam and directing primary ions of the beam onto the surface of the solid, and thereby causing sputtering of the surface for emission of secondary ions, b. analyzing the secondary ions by mass spectrometry to identify components of the sputtered/ions, the improvement which comprises: c. expanding the generated primary ion beam and thereafter extracting a portion of expanded beam, said extracted portion being of a uniform density of less than 10 7 amp. cm 2 and composing the primary ions directed onto the surface, whereby sputtering time of monolayers at the surface of the solid is prolonged and thereby the time for analyzing the sputtered ions is enlarged.

Claim 3

Process according to claim 1, and measuring the variation in intensity of individual types of sputtered ions with time while maintaining the current density constant.

Claim 4

Process according to claim 1, metal salt or oxide being present in the surface of the solid, and said analyzing comprises quantitatively analyzing the metal salt or oxide.

Claim 5

Process according to claim 1, said current density being 10 10 to 10 9 amp. cm. 2, and the degradation time being 5 - 50 hours.

Claim 6

Process according to claim 1, and maintaining a vacuum during said analysis of below 10 8 mm of mercury.

Claim 7

Apparatus for analyzing monolayers at the surfaces of solids comprising: a. a closed chamber having target support means for mounting therein, a specimen of the solid to be analyzed, b. vacuum means for maintaining a vacuum in the chamber, means for generating a primary ion beam and directing primary ions of the beam toward the surface of a specimen mounted in the target support means, d. interposed between the generating means and the target support means, means for expanding the generated ion beam and means for thereafter extracting a portion of the expanded beam, for providing an extracted primary ion beam having a uniform current density less than the density of the primary ion beam and less than 10 7 amp. cm 2, for bombarding the surface of a specimen mounted in the target support means, to cause sputtering of monolayers of the surface for emission therefrom of secondary ions, e. a mass spectrometer connected to the closed chamber for receiving secondary ions emitted by the specimen for analyzing said secondary ions.

Claim 8

Apparatus for analyzing monolayers at the surfaces of solids comprising: a. a closed chamber having target support means for mounting therein, a specimen of the solid to be analyzed, b. vacuum means for maintaining a vacuum in the chamber, means for generating a primary ion beam and directing primary ions of the beam toward the surface of a specimen mounted in the target support means, d. interposed between the generating means and the target support means, means for expanding the generated ion beam and means for thereafter extracting a portion of the expanded beam, for providing an extracted primary ion beam having a uniform current density less than the density of the primary ion beam and less than 10 7 amp. cm 2, for bombarding the surface of a specimen mounted in the target support means, to cause sputtering of monolayers of the surface for emission therefrom of secondary ions, e. a mass spectrometer connected to the closed chamber for receiving secondary ions emitted by the specimen for analyzing said secondary ions.

Claim 9

Apparatus according to claim 6, the mass spectrometer being outfitted with an open pulse multiplier as an ion detector.

Claim 10

Apparatus according to claim 7, and operatively connected in series to the open pulse multiplier, a pulse discriminator, a pulse forming device and an integrator.

Claim 11

Apparatus according to claim 6, the expanding means and the extracting means providing an extracted primary ion beam having a uniform current density of 10 10 to 10 9 amp. cm. 2, resulting in a degradation time Of 5 - 50 hours.