Analyzer microchannel plate combined with

A multipoint ion collector (also called the detector) consists of a large number of miniature electron multiplier elements assembled, or constructed, side by side over a plane. A multipoint collector can be an array, which detects a dispersed beam of ions simultaneously over a range of m/z values and is frequently used with a sector-type mass spectrometer. Alternatively, a microchannel plate collector detects all ions of one m/z value. When combined with a TOP analyzer, the microchannel plate affords an almost instantaneous mass spectrum. Because of their construction and operation, microchannel plate detectors are cheaper to fit and maintain. Multipoint detectors are particularly useful for situations in which ionization occurs within a very short space of time, as with some ionization sources, or in which only trace quantities of any substance are available. For such fleeting availability of ions, only multipoint collectors can measure a whole spectrum or part of a spectrum satisfactorily in the short time available. 

The method has evoked renewed interest, mainly due to the availability of improved Nd-YAG laser systems. Different types of detector, such as microchannel plates coupled to photodiodes and CCDs in combination with multichannel analyzers, make it possible to record an analytical line and an internal standard line simultaneously, so that analytical precision is considerably improved. By optimizing the ablation conditions and the spectral observations, detection limits obtained with the laser plume as source for AES are in the range 50-100 pg/g with standard deviations ca. 1 % [142],... 

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