562 Prof. K. T. Compton on Ionization and Production 



confirmation of the recent work of Horton and Miss Davies 

 and o£ Franck and Knipping. 



Even with intense ionization, there still remains an appre- 

 ciable photoelectric effect on the electrode, evidenced by the 

 fact that the ratio R = E//E^ approaches a value not far from 

 1*06 instead of unity as V a is indefinitely increased. This 

 is exactly, as would be expected, due to the continued presence 

 of 20- volt radiation and other radiation which may accompany 

 recombination. 



Fig-. 4. j)=0'17 mm. ; I. 20 =O6(10) b amp. 



700 



600 



500 



f~400 



1 E 

 S 300 



200 



100 

























! 

























































































'/ 































/ 





























i 



h 



























































i 































/ 























p_CL_ 







j 



/ 





















o 







/ 



/ 



























/ 



y 



/ 







R 





















A 



'/ 



















o 







^ 



^ 



■s 

























20 



22 



V 



26 



/ 2 £ 

 (Volts) 



30 



32 



R 

 1.60 



1.40 

 1.20 



1.00 



Between 20'2 and 25'5 volts it is seen that the ratio R 

 decreases from 1*9 to about 1*08 as the gas-pressure is 

 decreased from 0005 to 8 mm. This means that, as the 

 pressure increases, the proportion of ionization increases, as 

 shown by Table I. Here i/r is the ratio of the effect due 

 to ionization to that due to radiation. The exact values of 

 i/r are of no particular significance, since they will vary 

 according to the construction of the apparatus, but the 

 variation of i/r with p is important, 



