24 



NEUTRON EFFECTS ON ANIMALS 



surrounded by one inch of lead. Four 100-r chambers were placed in cage 4 

 and their discharge was compared with the integi'on discharge reading. 

 In successive trials the integron position was changed until a discharge of 

 29.3 divisions (full scale reading is 30 divisions) corresponded to a mean 

 dosage of 1.7 n in position 4. 



This relationship of integron discharge to cage 4 was checked thi-ee times 

 in the course of a year. 



ooz 





.0002 



.05 



r 



.0005 



B 



.00035 



.00012 



Fro. 6. Plan of the cyclotron room 



The 100 r chamber readings corresponding to a 29.3 division discharge 

 of the integron are given below: 



Total of Chamber Total Integron 



Readings Divisions 



Measurement of 3-27-45 274.5 n 29.3 X 160 



Measurement of 12-27-45 63.8 n 29.3 X 40 



Measurement of 4-2-46 102.7 n 29.3 X 60 



Total = 441.0 Total = 29.3 X 260 



These measurements give a mean position-4-dosage of 1.7 n for a 29.3 

 division discharge of the integron. 



Dosages for positions 5, 6, and 7 were determined directly by placing 

 four 100-r Victoreen ion chambers in the cages. The mean values obtained 

 for different segments of the cages are recorded below in terms of the posi- 

 tion-4-dosage obtained during the same exposure time : 



Ratio of dosage 



Dosage for 29.3 integron divisions. 



Cage 4 



100 

 1.7 n 



Cage 5 

 63.2 

 1.07 n 



Cage 6 



12.6 

 0.21 n 



Cage 7 

 395 

 6.72 n 



