A charged particle energy analyzer includes two hemispherical electrodes and means for developing an inverse square electric field in the gap between the two electrodes. An afocal charged particle lens arrangement is arranged to project a charged particle image of a sample into the electric field. Two baffles are disposed in the gap between the electrodes the baffles being effective to restrict the energy and angular divergence of the particles transmitted by the analyzer, the baffles being positioned so as to reduce the dependence of the energy and the orientation of the charged particles transmitted by the baffles on the position of the particles within the image. A two-dimensional detector is arranged to detect the charged particle image transmitted by the analyzer.

Surface contamination of silicon wafers is detected by a combined beam-deflecting magnet and magnetic spectrometer system. Heavy ions are directed onto the surface of a silicon wafer through the beam-deflecting magnet, and ions back-scattered from contaminants in the surface of the wafer pass through the magnetic spectrometer onto a focal-plane detector. One or more Einzel lenses prevent ions back-scattered from the silicon in the wafer from reaching the detector.

Disclosed is a method and apparatus for the measuring of isotopic ratio determination of elements on metallic, semi-conducting or insulating surface. The method involves pulsing an ion beam of at least about 2 KeV at a grazing incidence to impinge upon the surface of the sample. The ions which are recoiled off the surface of the sample are detected with a high resolution time-of-flight mass spectrometer which is comprised of at least one linear field free drift tube and at least one toroidal or spherical energy filter with a +/-V polarization to detect positive or negative ions. The method is applicable to a wide variety of elements from the periodic table and the ion source can be selected from a wide variety of ions which can be bombarding onto a sample. There are further methods for measuring of the ions under high pressure mass spectrometry, at pressures as high as 1 Torr. The apparatus can be adapted for the quantitation measurement of the elements on the surface under the high pressure conditions. Also disclosed is an apparatus for measuring ions. This apparatus can contain anywhere from 1 to 5 mass analyzers including measurements for recoiled and direct recoiled ions, for ion scattering spectroscopy, for secondary ion spectroscopy and for detecting backscattered ions. Mass analyzers are positioned at appropriate angles to detect the ions released from the bombardment of the sample. When measuring the backscattering ions, the apparatus is set up for two separate sources.

The invention provides apparatus and methods for performing time-of-flight (TOF) mass spectrometry. A TOF mass spectrometer of the present invention comprises one or more ion focusing electric sectors. At least one of the electric sectors is associated with an ion optical element. The ion optical elements comprise at least one adjustable electrode, such that the adjustable electrode is able to modify the potential experienced by an ion entering or exiting the electric sector with which it is associated.

The invention provides apparatus and methods for performing time-of-flight (TOF) mass spectrometry. A TOF mass spectrometer of the present invention comprises one or more ion focusing electric sectors. At least one of the electric sectors is associated with an ion optical element. The ion optical elements comprise at least one adjustable electrode, such that the adjustable electrode is able to modify the potential experienced by an ion entering or exiting the electric sector with which it is associated.