Anodized tantalum-sputtered glass

Figure 5. Anodized tantalum-sputtered glass slide on which normal intact plasma had resided for 12 min (more or less vertical zone from 1 to ) and where it had resided for a few seconds (area s, from to right...

Figure 2. Fibrinogen left by intact plasma between convex lens and anodized tantalum-sputtered glass slide. Only right half of pattern was exposed to antiserum to fibrinogen (see text).

Milton and Hutton [21] evaluated aluminum, copper, silver, indium, lead, and tantalum as possible secondary cathode materials. The first three candidates (Al, Cu, and Ag) sputtered at rates too high to allow production of ions characteristic of the glass sample (i.e., tended to produce too thick a metallic layer). Indium and lead are soft materials that lead to the overcompression of the insulator-cathode-sample sandwich, consistently resulting in electrical short-circuiting between the anode and cathode. Finally, tantalum does indeed exhibit the desirable characteristics for application as secondary cathode materials. Although not explicitly required, the fact that Ta is a getter element is likely to provide some added benefits as well. 

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