SPECTROPHOTOMETRY STUDY OF KATHODO-LUMIXESCENCE. 



H3 



DEPENDENCE OF KATHODO-LUMINESCENCE UPON CURRENT AND 

 DISCHARGE POTENTIAL. 



Since kathodo-luminescenee results from the bombardment of the lumi- 

 nescent substance by the kathode rays it is natural to expect a simple relation 

 between the intensity of luminescence and the velocity and number of the 

 kathode-ray particles. The experiments here described show that the form 

 of the luminescence spectrum is independent of both these factors. The 

 experiments show also that the intensity of luminescence is increased by 

 increasing either the velocity of the rays or the current in the tube. But 

 the conditions of the experiments were unfortunately not such as to permit 

 definite conclusions to be drawn regarding the quantitative relations. 



140 



120 



15 20 



25 30V-M. 



Fig. 148. Sidot blende. 



.58// 



The curves to the left are voltage-intensity curves for different wave-lengths. Curves I and II show the 

 luminescence spectra for discharge potentials of 11.600 volts and 7,700 volts respectively. Curve II I 

 shows the luminescence spectrum for 11,600 volts after the substance had been altered by the action of 

 the kathode rays. 



Several attempts were made to determine the relation between intensity 

 and current at a constant discharge potential. The current could be varied 

 through a wide range either by changing the speed of the Holtz machine 

 or by altering a resistance in multiple with the tube. The results make it 

 seem probable that the intensity of luminescence is proportional to the 

 current; but erratic changes in the conditions in the tube, due probably to 

 static charges on the walls, made it impossible to get entirely consistent 



