Active film multipliers

Hunter, K., Application of active film multipliers in ICP-MASS spectrometry, 2nd Australian Symposium on Applied ICP-Mass Spectrometry, Brisbane, Australia, May 17-19, 1993. 

ETP Scientific Inc. (1992) Active Film Multipliers — Handbook for Mass Spectrometry Applications, Auburn, MA, USA. 

Figure 16.26 MS detectors, (a) Discrete dynode model with active film (reproduced courtesy of ETP Scientific Inc.) (b) Continuous dynode model. Diagram of a channeltron the funnel shaped cathode permits the recovery of ions issuing from different trajectories. The curvature has the effect of preventing the positive ions which appear by the impact of electrons on the residual molecules and restricting therefore the production of further electrons (c) MicroChannel plate. Each plate consists of an array of tiny glass tubes. Each channel becomes a continuous dynode electron multiplier (d) Details of the conversion cathode. Multiplication of the electrons in a microtube (from illustration by Galileo USA).

In this expression, K is the thermodynamic equilibrium constant, which can be multiplied by Na/p (with Na equal to Avogadro s number) to obtain the commonly used equilibrium constants based on the molar bulk concentration reference state. It is important to note that the exponential term in the right-hand side of Equations 2.20 and 2.21 is an activity coefficient term. This term depends on the interaction field n z), which is nonlocal and therefore it couples with all the interactions and chemical equilibria in all regions of the film. 

Fermentation. The juice should be inoculated with an actively fermenting culture of one of the selected strains of S. fermentati. Such yeasts may be obtained from winery supply houses as pure cultures which must be multiplied to obtain enough inoculum for the large fermentation or as dried yeast which may be added directly to the juice. Alternatively, the juice may be fermented dry with one of the standard, non-film-forming yeasts, and then the dry white wine may be inoculated... 

When the thickness of Pi w as thin, the supputtcred Pt could not form a film but form many particles. If many particles arc created, the total surface area of the Pt will be larger than that of the planer film, because the total surface area will be determined by multiplying the number of Pt particle by the mean surface area of each particle. The active sites of a Pt surface area will increase in proportion to the thickness of Pt on this case before the supputtcred Pt form a film on a substrate. This will be the reason why there is the adequate thickness of Pt for the amount of Ni and H O product. 

When the surface is covered by one or more Aims, Fresnel analysis applied to each interface in turn followed by vector summation or the resulting multiply reflected beams leads to the Drude equations, which predict the A- and -values for a stack of films for which the thickness and refi active indices are known. 

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