to 



LU 



a 



lU 

 Q. 



< 



J 

 _J 



I- 

 z 



UJ 



a. 

 oc 



D 

 U 



DC 

 O 



I- 



o 

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2 IN 



4 6 8 10 12 14 



INCHES ALONG DRIFT TUBE (0 IS 0.95" FROM ANODE) 



16 



18 



8= 260 GAUSS, Be = 31.2 GAUSS, V= 2200 VOLTS, 1=38 MA 



Fig. 6 — The fields have been adjusted as in Fig. 5, for maximum extension of 

 the gain region, for noise power near 10,690 mc. Collector current measured with 

 the smallest aperture shows the greatest decline in amplitude of variations, as 

 well as advance in ripple phase relative to the current through the largest aperture. 



842 



