246 mieelock — Nature of Ionization Produced hy a Hays. 



effect of tlie field resolved along and at right angles to the path 

 of the a particle and less reconihination might be expected 

 with small dilierences of potential between the plates. 



14 



l'^' 



10 



Fig. 6. 





























^^ 



,^^ 



- — 













B 























/ 



y 



^ 



■ " 



-v 









































1 























' 



( 

















































10 20 



40 60 



Volts per cm. 



80 



100 



120 



Fig. 6. — A, Experimental curve. B, Calculated curve. 



This suggested experiments in which the field would be 

 strictly parallel to the trajectory of the a particle. 



IV. To Test the Effect of Inclination of the Columns. 



For these experiments the ordinary Bragg chamber, used 

 above, was replaced by an ionization chamber consisting of a 

 spherical brass cap of radius 3*^" for an upper plate, a spherical 

 cap of wire gauze, radius 2-6'^'", for the lower plate of the 

 ionization chamber. This with another spherical gauze cap, 

 radius 2'2"", formed a second ionization chamber which pre- 

 vented any stray ions from getting into tlie ionization chamber 

 proper. The caps were placed 4°"" apart. The radio-active 

 source was placed at the center of the spheres of which the 

 caps were a part and only a small pencil of rays was used. 



The curves obtained with the spherical chamber, in which 

 the Held was always parallel to the path of the a particle, 

 differ very little from tliose obtained witli the Bragg chamber; 

 however they do show slightly more recombination at low 

 voltages, which would be expected. The experimental curve 

 was found to lie below the calculated curve except when 

 an intense electric field was applied. 



