MEASUREMENT OF X-RAYS AND RADIUM 



61 



2.0 



1.8 



1.6 



ex 

 o 

 o 



E 

 E 



1.2 



>. 0.8 



X. 



0.6 

 0.4 

 0.2 



^ ' 20 40 60 80 100 120 140 160 180 200 



Kilovolts CMax) 



Fig. 10. — Half-value layers of copper. (Holthusen.) 



20 30 40 50 60 70 80 90 100 120 130 

 Kilovoi+s (Mcx) 



Fig. 11. — Half-value layers of aluminum. (Holthusen.) 



