BEAM FORMATION WITH ELECTRON GUNS 



401 



Q 



LL 



lU 



1.0 12 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 40 



rcAa 



Fig. 10 — Curve used in finding ?•«+', the direction of a nonthermal edge elec- 

 tron as it enters the drift region. (See equation 33.) 



(27r€o(277 Fa) ''), (28) is integrated numerically using the BTL analog com- 

 puter to obtain a and r^ as functions of axial distance along the beam, 

 (c) Knowing a and Ve , other beam parameters such as current dis- 

 tribution and the radius of the circle which would encompass a given 

 percentage of the total current can be found from Figs. 6 and 7. 



X 



tvi 



U 



20 



15 



10 



5 







-5 



-10 



-15 



-20 



-25 



-30 



20 

 18 

 16 

 14 



12 



rO 

 O 



10 X 



(J 



8 



2 





 10 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 



tc/fa 



Fig. 11 — Curves used in evaluating o-+', the slope of the trajectory of a thermal 

 electron with standard deviation a as it enters the drift region. (See equation 35.) 



