BETA-RAY DISTRIBUTION OF ENERGY 



67 



01 



# 



1000 2000 3000 4000 



Values of Hr ~ velocity 



5000 



Fig. II-6. This is the beta-ray spectrum of radium B originally obtained by R. W. 

 Gurney [1925]. It shows the velocity distribution of the beta rays from a radon 

 source. The humps are homogeneous velocity groups superimposed on the general 

 electron emission limited by the broken curve. The number of electrons composing 

 the humps are small compared with those in the continuous spectrum, so that one 

 practically always deals with a decidedly non-homogeneous distribution of velocities. 



TABLE II-4 

 Prominent Homogeneous Beta-Ray Velocity Groups 



Relative Intensity 



Energy in Kilovolts 



17 

 11 

 80 

 91 

 100 

 16 



7.6 

 2.4 



4.7 



50 

 20 

 10 



Radium B 



Radium C 



Radium D 



The relative intensity of these radiations is very small as compared with the general total back- 

 ground radiation. Composite results of Ellis and Skinner, Proc. Roy. Soc, A 105, 60, 1924; Ellis and 

 Astor, ibid., 119, 645, 192S; Ellis and Wooster, ibid., 114, 276, 1927; Ellis and Astor, ibid., 129, 180, 1930. 



