22 



NEUTRON EFFECTS ON ANIMALS 



tensity from 6 million electron volt neutrons. Hence positions 3 and 2 

 received neutron radiation with a maximum intensity of approximately 

 he same energy. 



z 



< 



CL ISO 



8 



I 



O 



z 



< 



u 



DC 

 li. 

 O 



160 



<-^ 140 



z 



< 



UJ 



cr 



en 



u 



CD 



< 



I 

 u 



120 



— 100 



12 3 4 



INCHES OF PARAFFIN 



Fig. 4. Comparison of the neutron intensity spectra in positions 4, 3 and 2. 

 Position #4. O = Position ;^3. A = Position j^2. 



D = 



NEUTRON RADIATION INTENSITY 



The method of intensity measurement followed that of Aebersold and 

 Lawrence (3). There is at present no well-defined standard of fast neutron 

 radiation intensity. The method of Aebersold and Lawrence seemed the 

 most practical and, as we worked with a neutron spectrum similar to theirs, 

 a comparison of results was easier. An important advantage in this method 

 is that all radiation intensity measurements are made with a Victoreen 100 r 

 chamber. These chambers are commonly used in X-ray work and are 

 readily availaMe. 



The Victoreen chamber gives its reading in r (Roentgen) units. AVe 

 have followed the practice of Aebersold and Lawrence and called these 

 readings n (for neutron radiation intensity) units. This was done for two 



