Simple surface ionization detector with field reversal for absolute ionization coefficient and ionic and neutral desorption measurements

摘要

Recent absolute reactive scattering experiments have demonstrated the need for and usefulness of absolute flux measuring molecular beam detectors. A field reversal detector of the type described here can conveniently and accurately (≪±3%) measure the absolute flux of molecular beams of easily ionizable substances, without external calibrations or surface condition or surface temperature changes. The detector is mechanically very similar to the common surface ionization detector and uses uncomplicated electronics. With such a detector the neutral and ionic desorption rates may also be accurately determined separately. Thus the values of the true desorption parameters may be measured; such values have usually not been produced by previous methods for desorption rate measurements.