ROENTGEN ABSORPTION HISTOSPECTROSCOPY 



131 



TABLE IV 

 Elementary Composition of Muscle (Engstrom, 1946) 



S2.23910-3 



21.960-10-3 



heaviest elements (the My is the greatest of Mj-y). The smallest 

 quantity of an element, in g./mm.^, which can be determined is given 

 in Figure 17. This is based on the fact that the smallest intensity 

 difference between ii and i2 which can be measured with certainty is 

 about 5%. 



1.0 



0.8 



?ti:o.6 



0.4 



02 



WAVE LENGTH, A 



Fig. 18. Absorption of roent- 

 gen radiation of different wave- 

 lengths in paraffin of varying 

 thickness. From Engstrom 

 (1946) 



a. 10' 



8 10 



6C 7N 80 llNal2Mg 15P 16S 17CI 19K20Ca 26Fe 



Fig. 19. Appropriate layer thicknesses 

 for determinations of different elements 

 in muscular tissue. The solid columns 

 indicate the layer thickness when the 

 K-absorptibn edge is used; the hatched, 

 the Ljjj edge. From Engstrom (1946) 



