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BELL SYSTEM TECHNICAL JOURNAL 



0.2 0.4 0.6 0.8 1.0 !.2 1.4 1.6 1.8 2.0 2.2 24 



X 

 ^0 



Fig. 137. — Variation of potential in the repel ler region vs distance to give the charac- 

 teristics shown in Fig. 7.1. 



Fig. 138.— Electrodes to achieve approximately the potential variation in the drift 

 region shown in Fig. 7.2. 



