Efficiency connection with voltage

Fig. 9-3. Comparison of 50-kv, 40-ma (dotted line) spectra with 100-kv, 20-ma (solid line) spectra of hafnium and tantalum, showing efficient excitation of the K spectra at the higher voltage. The higher voltage is particularly useful in connection with analyses of niobium-tantalum mixtures and zirconium-hafnium mixtures which are difficult at the lower voltage because of the interference of the K lines of the lighter elements with the L spectra of the heavier elements. (Courtesy of M. L. Salmon, Fluo-X-Spec Analytical Laboratory, Denver, Colo.)...

Below 30 MHz, the cathode can be grounded to RF voltages by simply bypassing the filament connections with capacitors, as shown in Fig. 5.69(a). Above 30 MHz, this technique does not work well because of the stray inductance of the filament leads. Notice that in Fig. 5.69(b), the filament leads appear as RF chokes, preventing the cathode from being placed at RF ground potential. This causes negative feedback and reduces the efficiency of the input and output circuits. 

Phase 1 will be soon completed. Different electrode geometries were investigated, and a dedicated electrostatic device constmcted in order to facilitate electrode testing. The electrocyclone collection efficiency is in fact directly connected with the current intensity which can be obtained imder a specified voltage. So in this device, intensity versus voltage is measured, outside the dust collection bench. Fig. 4 shows the evolution of current intensity for the snccessive types of electrode. 

The octopole configuration is similar to the quadrupole and hexapole in affording a good ion guidance system in its all-RF mode. The poles are connected in two pairs of four nonadjacent rods, and each pair is connected to an RF voltage supply, 180° out of phase with each other. The octopole is even more efficient than the hexapole as an ion guide. 

In single-phase bridge circuits for ac connections and for very low ac output voltages below 5 V, single-phase center tap circuits are used as rectifier circuits for CP transformer-rectifiers. They have an efficiency of 60 to 15% and a residual ripple of 48% with a frequency of 100 Hz. A three-phase bridge circuit for three-phase alternating current is more economical for outputs of about 2 kW. It has an efficiency of about 80 to 90% and a residual ripple of 4% with a frequency of 300 Hz. The residual ripple is not significant in the electrochemical effect of the protection current so that both circuits are equally valid. 

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