238 



20 



18 



16 



14 



a 12 

 o 



S 10 



Wheelock — Nature of Ionization Produced by a Hays 



Fig. 3. 





 O 4 









^ , 







B 







1 















,/^ 



^ 



--- 







" A ~ 

































































































' 















C 







1 1 



( 

























































D 









. 



r^l 













































20 



40 



80 120 

 Volts per cm. 



160 



200 



A = a ray curve, parallel field. 



B =: a ray curve, perpendicular field. 



C := ^ and y ray curve, parallel field. 



T) — /3 and y ray curve, perpendicular field. 



The fact that for /3 and 7 rajs, saturation is obtained for 

 small potential differences between the plates, has been 

 explained by Kleeman as due to the electron, emitted in 

 the act of ionization, being shot o£E with a velocity great 

 enough to effect complete separation from the remaining 

 positive ion, and therefore initial recombination would be 

 negligible. 



General recombination would have very little effect in this 

 case, since it is volume ionization from a very weak source. 



11. Evidence of Columnar Ionization. 



When a gas is ionized by /3 or <y rays, it has been seen that 

 saturation is obtained at small voltages, if the ionization is small. 

 It is found by experiment that as the ionization increases, a 

 stronger field is necessary to obtain the saturation value. 



