CHARACTERISTIC X-RAY EMISSION SPECTRA 



11 



Each adjustment necessitates radiation of an x-ray quantum or bundle 

 of energy designated as a " photon " because of the interatomic energy 

 exchange which is involved. The radiations originating as the result 

 of an adjustment of the electrons from the L to the K configuration 

 are called the characteristic K series (Table 1-2), i.e., characteristic 



TABLE 1-2 



Prominent X-Ray Emission Lines 

 Wavelengths in 10 -8 cm (A) 



L series 



11.5 



100 



1.4845 

 1.4735 



5.400 

 5.394 



M series 



«i 



6.973 



Excitation Potentials in Kilovolts of the 



of the tungsten atom. The radiations emitted as the adjustment pro- 

 gresses from the M to the L configuration are called the L series. Be- 

 cause of their long wavelength (X = 6.9 A), these radiations never 

 appear outside of a tungsten-target Coolidge tube owing to the opacity 

 of the glass for these " extremely soft " x-rays. 



When the radiations from a tungsten target are examined with the 

 aid of an x-ray spectrometer, sharp peaks are found on the emission 

 curve. These are resolved into four principal homogeneous emissions, 

 the Ka 2 , Kai, K&x, and K& 2 , of which the Kai emission is the most 

 intense (Table 1-2). 



