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BELL SYSTEM TECHNICAL JOURNAL 



and this amount is the same as would occur if the charge density of the 

 hill and valley checkers were uniformly distributed over the entire 

 surface. On the other hand for /3 between and — 1, i.e., for points 



10.1 



9.9 



O 



> 9.8 



9.7 



9.6 



9.5 



-1 



200 



400 600 800 1000 1200 1400 1600 



Z— DISTANCE FROM CATHODE IN CENTIMETERS 



1800 X10"8 



'ig. 12 — Potential energy vs. distance from the surface above the center of the dif- 

 ferent subcheckers of the hill and valley checkerboard; zero applied field. 



on a valley checker, the value of Zc depends on the particular point 

 chosen. .The reduction in the work function is less than 12007r/p and 

 varies from point to point. 



The next step is to ascertain the effect of an accelerating field on 

 these P vs. z curves. Figure 13 shows this for /S = 1, 2. i. "~ :i. ~ 2 

 and — 1, respectively, for F = 5000 volts/cm. The effect of the 

 field is to decrease Zc and /*„,. From Figs. 12 and 13 it follows that the 

 decrease in Zc and in P^ due to F varies with j8 and is much larger for 



