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7 | <BODY> |
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8 | <!-- Created by: Makoto Asai, 30-Mar-2006 --> |
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9 | |
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10 | <BR> |
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11 | |
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12 | <TABLE WIDTH="100%" > |
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13 | <TR> |
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14 | <TD> |
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15 | |
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16 | </A> |
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17 | <A HREF="index.html"> |
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18 | <IMG SRC="../../../../resources/html/IconsGIF/Contents.gif" ALT="Contents" HEIGHT=16 WIDTH=59></A> |
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19 | <A HREF="physicsTable.html"> |
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20 | <IMG SRC="../../../../resources/html/IconsGIF/Previous.gif" ALT="Previous" HEIGHT=16 WIDTH=59></A> |
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21 | <A> |
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22 | <IMG SRC="../../../../resources/html/IconsGIF/NextGR.gif" ALT="Next" HEIGHT=16 WIDTH=59></A> |
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23 | </TD> |
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24 | <P> |
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25 | |
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26 | <TD ALIGN=RIGHT><FONT COLOR="#238E23"><FONT SIZE=-1> |
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27 | <B>Geant4 User's Guide</B></FONT></FONT> |
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28 | <BR><FONT COLOR="#238E23"><FONT SIZE=-1> |
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29 | <B>For Application Developers</B></FONT></FONT> |
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30 | <BR><FONT COLOR="#238E23"><FONT SIZE=-1> |
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31 | <B>Tracking and Physics</B></FONT></FONT></TD> |
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32 | </TR> |
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33 | </TABLE> |
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34 | <P><BR> |
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35 | |
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36 | <CENTER><FONT COLOR="#238E23"><FONT SIZE=+3> |
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37 | <B>5.7 User limits</B></FONT></FONT> |
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38 | </CENTER> |
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39 | <P><BR> |
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40 | |
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41 | <HR ALIGN="Center" SIZE="7%"> |
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42 | <P> |
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43 | |
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44 | <a name="5.7.1"> |
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45 | <H2>5.7.1 General Concepts</H2></a> |
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46 | The user can define artificial limits affecting to the Geant4 tracking. |
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47 | <pre> |
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48 | G4UserLimits(G4double uStepMax = DBL_MAX, |
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49 | G4double uTrakMax = DBL_MAX, |
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50 | G4double uTimeMax = DBL_MAX, |
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51 | G4double uEkinMin = 0., |
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52 | G4double uRangMin = 0. ); |
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53 | </pre> |
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54 | <table border=1 cellpadding=8> |
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55 | <tr><td><tt>uStepMax</tt> |
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56 | <td>Maximum step length |
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57 | <tr><td><tt>uTrakMax</tt> |
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58 | <td>Maximum total track length |
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59 | <tr><td><tt>uTimeMax</tt> |
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60 | <td>Maximum global time for a track |
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61 | <tr><td><tt>uEkinMin</tt> |
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62 | <td>Minimum remaining kinetic energy for a track |
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63 | <tr><td><tt>uRangMin</tt> |
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64 | <td>Minimum remaining range for a track |
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65 | </table> |
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66 | Note that <tt>uStepMax</tt> is affecting to each step, while all other limits are |
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67 | affecting to a track. |
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68 | <p> |
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69 | The user can set <tt>G4UserLimits</tt> to logical volume and/or to a region. |
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70 | User limits assigned to logical volume do not propagate to daughter volumes, while |
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71 | User limits assigned to region propagate to daughter volumes unless daughters |
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72 | belong to another region. If both logical volume and associated region have user |
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73 | limits, those of logical volume win. |
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74 | |
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75 | <a name="5.7.2"> |
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76 | <H2>5.7.2 Processes co-working with G4UserLimits</H2></a> |
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77 | |
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78 | In addition to instantiating <tt>G4UserLimits</tt> and setting it to logical volume |
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79 | or region, the user has to assign the following process(es) to particle types he/she |
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80 | wants to affect. If none of these processes is assigned, that kind of particle is not |
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81 | affected by <tt>G4UserLimits</tt>. |
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82 | <dl> |
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83 | <dt>Limitation to step (<tt>uStepMax</tt>) |
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84 | <dd><tt>G4StepLimiter</tt> process must be defined to affected particle types. |
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85 | This process limits a step, but it does not kill a track. |
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86 | |
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87 | <dt>Limitations to track (<tt>uTrakMax, uTimeMax, uEkinMin, uRangMin</tt>) |
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88 | <dd><tt>G4UserSpecialCuts</tt> process must be defined to affected particle types. |
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89 | This process limits a step and kills the track when the track comes to one of these |
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90 | limits. Step limitation occurs only for the final step. |
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91 | </dl> |
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92 | <p> |
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93 | Example of <tt>G4UserLimits</tt> can be found in examples/novice/N02 : |
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94 | see <tt>DetectorConstruction</tt> and <tt>PhysicsList</tt>. |
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95 | |
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96 | <BR><BR> |
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97 | <HR><A HREF="../../../../Authors/html/subjectsToAuthors.html"> |
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98 | <I>About the authors</A></I> |
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99 | </BODY> |
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100 | </HTML> |
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