High energy neutral beams

Positive ions are produced by bombarding neutral atoms or molecules in the vapour phase with a high energy electron beam in the ionisation chamber. One (or sometimes two) electron are ejected from the outer most shells. 

The secondary Ion extraction optics should Include an Immersion lens above the sample surface to maximize secondary Ion transmission from the sample surface to the mass spectrometer. An electrostatic analyzer should again be used to filter out high-energy neutral particles and photons from the secondary Ion beam. Energy analysis of the secondary Ions Is generally not necessary, but can be used to vary the amount of fragmentation observed In the mass spectrum (9). 

Electron ionization (El) is the traditional method for ionizing a neutral gas-phase compounds. A high-energy electron beam (often 70 eV) is allowed to pass through the sample vapor at relatively low pressure, leading to the general ionization equation... 

The bombardment of a neutral molecule with a beam of high energy electrons results in the formation of a molecular (or... 

The bombarding of the specimen surface by the primary beam of high energy ions leads to the ejection (sputtering) of both neutral and charged (+/—) species from the surface. The ejected species may include atoms, clusters of atoms and molecular fragments. The ions enter an extraction lens and the polarity of the applied voltages determines the polarity of the secondary ions that enter the analyser. 

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