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| 6 | |
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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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| 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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