compton: size and shape of electrons 



rigid spherical electron which is subject to rotation should lie 

 between curves I and II for the range of a/X here plotted. 



Unfortunately the experimental data are too meager to sub- 

 mit these formulae to accurate quantitative test. There are, 



.12 



cr 

 P 



■I'f 



.13. 



.16 



.0? 



.06 



M 



,01 



.05 



.10 



.15 



.20 



.Z5 a/A 0.30 



Fig. 1. Mass absorption coefficient for electrons (I) in the form of rigid 

 spherical shells incapable of rotation, and (II) in the form of perfectly flexible 

 spherical shells. The number of electrons per atom is taken as 13. 



however, three points on the curve w^hich are established with 

 Some accuracy. Barkla^ has found that for relatively long X-rays 

 the light elements scatter accurately according to equation (1), 

 so that the part of the curves where a/X is small is verified. 



^ Barkla and Dunlop. Phil. Alag. 



