1 | \chapter{Materials} |
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2 | |
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3 | \section{Design Philosophy} |
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4 | |
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5 | The design of the materials category reflects what exists in nature: materials |
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6 | are made of a single element or a mixture of elements, and elements are made |
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7 | of a single isotope or a mixture of isotopes. Because the physical |
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8 | properties of materials can be described in a generic way by quantities which |
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9 | can be specified directly, such as density, or derived from the element |
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10 | composition, only concrete classes are necessary in this category. |
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11 | |
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12 | The material category implements the facilities necessary to describe the |
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13 | physical properties of materials for the simulation of particle-matter |
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14 | interactions. Characteristics like radiation and interaction length, |
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15 | excitation energy loss, coefficients in the Bethe-Bloch formula, shell |
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16 | correction factors, etc., are computed from the element, and if necessary, |
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17 | the isotope composition. |
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18 | |
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19 | The material category also implements facilities to describe surface |
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20 | properties used in the tracking of optical photons. |
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21 | |
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22 | \section{Class Design} |
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23 | |
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24 | The object-oriented design of the 'materials' related classes |
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25 | is shown in the class diagram: |
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26 | Fig. \ref{figure:materials-1}. |
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27 | The diagram is described in the Booch notation. |
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28 | |
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29 | |
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30 | \begin{figure}[ht!] |
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31 | \includegraphics[angle=0,scale=0.7]{OOAnalysisDesign/Materials/classDgmMaterials.eps} |
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32 | \vspace{10pt} |
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33 | \caption{Materials} |
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34 | \label{figure:materials-1} |
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35 | \end{figure} |
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36 | |
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37 | |
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38 | \section{Status of this chapter} |
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39 | |
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40 | 27.06.05 section on design philosophy add (from Geant4 general paper) by |
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41 | D.H. Wright \\ |
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42 | |
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43 | |
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44 | |
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