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BELL SYSTEM TECHNICAL JOURNAL 



hundreds of millions — the number of protons received and detected 

 in the conical chamber behind the absorption-foils of mica, per hundred 

 million alpha-corpuscles impinging on the sheet of aluminium. This 

 sheet was so thick that all of the impinging corpuscles were swallowed 

 up in it. Thus, the uppermost of the curves relates to aluminium 

 subjected to alpha-rays of all ranges from 3.72 centimeters down to nil; 

 and the numbers attached to the others likewise stand for the maximum 



20 25 30 35 40 45 



AIR-EQUIVALENT IN CENTIMETERS 



Fig. 6 — Integral distribution-in-range curves for protons emitted from disrupted 

 nuclei of aluminium atoms (H. Pose). 



ranges represented among the particles as they approached the nuclei. 

 By differentiating these curves one would get distribution-in-range 

 curves for the protons. I will therefore refer to them, and to those of 

 Figs. 2, 7 and 8, as "integral distribution-in-range curves." 



Ignoring for the moment the left-hand half of the diagram, consider 

 the other. The two lowest of the curves do not reach it: hence, alpha- 

 particles of 2.23-centimeter range or less do not have the power of ex- 

 pelling protons with 30-centimeter range or greater. The other three 



