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BELL SYSTEM TECHNICAL JOURNAL 



obtained with the first design, pointing to a more effective trapping of the 

 sputtered material. 



Weight loss measurements made under a variety of pulsing conditions 

 show that though the rate of cathode erosion is somewhat dependent on the 



Fig. 9 — Photomicrographs (X50) of sections showing anode deposits for (a) unit gap 

 shown in Fig. 7, {h) unit gap shown in Fig. 10. 



pulse duration, it depends to a much greater extent on gap design. Erosion 

 rate measurements in terms of grams per coulomb are shown in Fig. 1 1 for 

 the two gap designs there indicated and for pulse durations varying from one 

 to five microseconds. It is clear that the open gap type of design in which 

 the cathode is small leads to a loss which is at least five fold greater than 



