680 



TABLE 738.— ALPHA-RAY SPECTRA OF SOME NATURAL RADIOACTIVE 



MATERIALS 



It is sometimes stated that all alpha-particles from any one source are emitted with the same 

 energy or velocity. This is in the main true for most of the particles but careful measurements 

 have shown that this is not always the case. For some time it was known that occasionally an 

 alpha-particle had a range much longer than average, which, of course, means a high initial 

 velocity. 



SMITHSONIAN PHYSICAL TABLES 



