| 1 | <HTML>
|
|---|
| 2 | <HEAD>
|
|---|
| 3 | <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
|
|---|
| 4 | <META NAME="GENERATOR" CONTENT="Mozilla/4.04 [en] (X11; I; AIX 4.1) [Netscape]">
|
|---|
| 5 | </HEAD>
|
|---|
| 6 |
|
|---|
| 7 | <BODY>
|
|---|
| 8 | <!-- Created by: Makoto Asai, 30-Mar-2006 -->
|
|---|
| 9 |
|
|---|
| 10 | <BR>
|
|---|
| 11 |
|
|---|
| 12 | <TABLE WIDTH="100%" >
|
|---|
| 13 | <TR>
|
|---|
| 14 | <TD>
|
|---|
| 15 |
|
|---|
| 16 | </A>
|
|---|
| 17 | <A HREF="index.html">
|
|---|
| 18 | <IMG SRC="../../../../resources/html/IconsGIF/Contents.gif" ALT="Contents" HEIGHT=16 WIDTH=59></A>
|
|---|
| 19 | <A HREF="physicsTable.html">
|
|---|
| 20 | <IMG SRC="../../../../resources/html/IconsGIF/Previous.gif" ALT="Previous" HEIGHT=16 WIDTH=59></A>
|
|---|
| 21 | <A>
|
|---|
| 22 | <IMG SRC="../../../../resources/html/IconsGIF/NextGR.gif" ALT="Next" HEIGHT=16 WIDTH=59></A>
|
|---|
| 23 | </TD>
|
|---|
| 24 | <P>
|
|---|
| 25 |
|
|---|
| 26 | <TD ALIGN=RIGHT><FONT COLOR="#238E23"><FONT SIZE=-1>
|
|---|
| 27 | <B>Geant4 User's Guide</B></FONT></FONT>
|
|---|
| 28 | <BR><FONT COLOR="#238E23"><FONT SIZE=-1>
|
|---|
| 29 | <B>For Application Developers</B></FONT></FONT>
|
|---|
| 30 | <BR><FONT COLOR="#238E23"><FONT SIZE=-1>
|
|---|
| 31 | <B>Tracking and Physics</B></FONT></FONT></TD>
|
|---|
| 32 | </TR>
|
|---|
| 33 | </TABLE>
|
|---|
| 34 | <P><BR>
|
|---|
| 35 |
|
|---|
| 36 | <CENTER><FONT COLOR="#238E23"><FONT SIZE=+3>
|
|---|
| 37 | <B>5.7 User limits</B></FONT></FONT>
|
|---|
| 38 | </CENTER>
|
|---|
| 39 | <P><BR>
|
|---|
| 40 |
|
|---|
| 41 | <HR ALIGN="Center" SIZE="7%">
|
|---|
| 42 | <P>
|
|---|
| 43 |
|
|---|
| 44 | <a name="5.7.1">
|
|---|
| 45 | <H2>5.7.1 General Concepts</H2></a>
|
|---|
| 46 | The user can define artificial limits affecting to the Geant4 tracking.
|
|---|
| 47 | <pre>
|
|---|
| 48 | G4UserLimits(G4double uStepMax = DBL_MAX,
|
|---|
| 49 | G4double uTrakMax = DBL_MAX,
|
|---|
| 50 | G4double uTimeMax = DBL_MAX,
|
|---|
| 51 | G4double uEkinMin = 0.,
|
|---|
| 52 | G4double uRangMin = 0. );
|
|---|
| 53 | </pre>
|
|---|
| 54 | <table border=1 cellpadding=8>
|
|---|
| 55 | <tr><td><tt>uStepMax</tt>
|
|---|
| 56 | <td>Maximum step length
|
|---|
| 57 | <tr><td><tt>uTrakMax</tt>
|
|---|
| 58 | <td>Maximum total track length
|
|---|
| 59 | <tr><td><tt>uTimeMax</tt>
|
|---|
| 60 | <td>Maximum global time for a track
|
|---|
| 61 | <tr><td><tt>uEkinMin</tt>
|
|---|
| 62 | <td>Minimum remaining kinetic energy for a track
|
|---|
| 63 | <tr><td><tt>uRangMin</tt>
|
|---|
| 64 | <td>Minimum remaining range for a track
|
|---|
| 65 | </table>
|
|---|
| 66 | Note that <tt>uStepMax</tt> is affecting to each step, while all other limits are
|
|---|
| 67 | affecting to a track.
|
|---|
| 68 | <p>
|
|---|
| 69 | The user can set <tt>G4UserLimits</tt> to logical volume and/or to a region.
|
|---|
| 70 | User limits assigned to logical volume do not propagate to daughter volumes, while
|
|---|
| 71 | User limits assigned to region propagate to daughter volumes unless daughters
|
|---|
| 72 | belong to another region. If both logical volume and associated region have user
|
|---|
| 73 | limits, those of logical volume win.
|
|---|
| 74 |
|
|---|
| 75 | <a name="5.7.2">
|
|---|
| 76 | <H2>5.7.2 Processes co-working with G4UserLimits</H2></a>
|
|---|
| 77 |
|
|---|
| 78 | In addition to instantiating <tt>G4UserLimits</tt> and setting it to logical volume
|
|---|
| 79 | or region, the user has to assign the following process(es) to particle types he/she
|
|---|
| 80 | wants to affect. If none of these processes is assigned, that kind of particle is not
|
|---|
| 81 | affected by <tt>G4UserLimits</tt>.
|
|---|
| 82 | <dl>
|
|---|
| 83 | <dt>Limitation to step (<tt>uStepMax</tt>)
|
|---|
| 84 | <dd><tt>G4StepLimiter</tt> process must be defined to affected particle types.
|
|---|
| 85 | This process limits a step, but it does not kill a track.
|
|---|
| 86 |
|
|---|
| 87 | <dt>Limitations to track (<tt>uTrakMax, uTimeMax, uEkinMin, uRangMin</tt>)
|
|---|
| 88 | <dd><tt>G4UserSpecialCuts</tt> process must be defined to affected particle types.
|
|---|
| 89 | This process limits a step and kills the track when the track comes to one of these
|
|---|
| 90 | limits. Step limitation occurs only for the final step.
|
|---|
| 91 | </dl>
|
|---|
| 92 | <p>
|
|---|
| 93 | Example of <tt>G4UserLimits</tt> can be found in examples/novice/N02 :
|
|---|
| 94 | see <tt>DetectorConstruction</tt> and <tt>PhysicsList</tt>.
|
|---|
| 95 |
|
|---|
| 96 | <BR><BR>
|
|---|
| 97 | <HR><A HREF="../../../../Authors/html/subjectsToAuthors.html">
|
|---|
| 98 | <I>About the authors</A></I>
|
|---|
| 99 | </BODY>
|
|---|
| 100 | </HTML>
|
|---|
