Bragg rule

The stopping power of a material is defined as the energy loss per distance travelled in the material, dE/dz, and the Bragg rule may be expressed more generally, if the stopping cross-sections for each element are known ... 

STOPPING POWER, LET, AND FLUCTUATIONS 2.1. Bohr s Theory and the Bragg Rule... 

The preceding was developed mostly for atomic or molecular targets, and, indeed, much experimental work has been carried on gaseous samples. If one thinks along the lines of the Bragg rule [21], then one would not expect such considerations to differ much from results obtained on solid samples, and for most molecular or van der Waals solids - indeed they do not [22]. 

The Bragg Rule can also be somewhat generalized so that a system is composed of a number of polyatomic fragments, akin to functional groups (vide infra) ... 

In fact, these results are not surprising. As most biological molecules are primarily hydrides of the later first row atoms, they all have quite similar excitation spectra, and consequently quite similar mean excitation energies. The Bragg Rule is well obeyed in these systems, as the mean excitation energies of biological sysfems is bofh sfable and consistent. 

J. Oddershede, J.R. Sabin, Bragg Rule Additivity of Bond Stopping Cross Sections, Nucl. Inst. Meth. B 42 (1989) 7. 

The function f e) is usually not completely known. It can either be obtained semi-empirically or can be calculated using the Bragg rule which states that the stopping number of a molecule is the sum of the stopping... 

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