SPARK GAP SWITCHES FOR RADAR 



577 



that of the "end sparking" type of gap. The smaller loss in the case of the 

 latter shows that much more material returns to the cathode for resputtering 



Fig. 10 — Photograph and radiograph — actual size — of end sparking unit gap, after 

 operating 700 hours with a 65-anii)ere pulse of one microsecond duration and repeated 

 1660 times a second. 



than in the case of the former and supports the use of the unit type gap in 

 which this process can be utilized. A cylindrical cathode enclosing a rod 



