1 | <html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>FAQ.5. Physics and cuts</title><link rel="stylesheet" href="../xml/XSLCustomizationLayer/G4HTMLStylesheet.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.71.1"><link rel="start" href="index.html" title="Geant4 User's Guide for Application Developers"><link rel="up" href="ch10.html" title="Chapter FAQ. Frequentry Asked Questions"><link rel="prev" href="ch10s04.html" title="FAQ.4. Tracks and steps"><link rel="next" href="ch10s06.html" title="FAQ.6. Visualization"><script language="JavaScript"> |
---|
2 | function remote_win(fName) |
---|
3 | { |
---|
4 | var url = "AllResources/Detector/geometry.src/" + fName; |
---|
5 | RemoteWin=window.open(url,"","resizable=no,toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=0,copyhistory=0,width=520,height=520") |
---|
6 | RemoteWin.creator=self |
---|
7 | } |
---|
8 | </script></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">FAQ.5. |
---|
9 | Physics and cuts |
---|
10 | </th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ch10s04.html"><img src="AllResources/IconsGIF/prev.gif" alt="Prev"></a> </td><th width="60%" align="center">Chapter FAQ. |
---|
11 | Frequentry Asked Questions |
---|
12 | </th><td width="20%" align="right"> <a accesskey="n" href="ch10s06.html"><img src="AllResources/IconsGIF/next.gif" alt="Next"></a></td></tr></table><hr></div><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="qanda.PhysicsCuts"></a>FAQ.5. |
---|
13 | Physics and cuts |
---|
14 | </h2></div></div></div><div class="qandaset"><table border="0" summary="Q and A Set"><col align="left" width="1%"><tbody><tr class="question"><td align="left" valign="top"><a name="qanda.PhysicsCuts.HowProdCuts"></a><a name="id554957"></a><b>Q:</b></td><td align="left" valign="top"><p> |
---|
15 | How do production cuts (in range) work in Geant4 ? Are they also used |
---|
16 | in tracking ? If a particle has an energy lower than the converted cut |
---|
17 | in energy for the given material and the distance to the next boundary |
---|
18 | is smaller than the cut in range, is the particle killed ? |
---|
19 | </p></td></tr><tr class="answer"><td align="left" valign="top"><b>A:</b></td><td align="left" valign="top"><p> |
---|
20 | Geant4 does <span class="bold"><strong>NOT</strong></span> have a "tracking cut". |
---|
21 | The toolkit's default behaviour is to track particles down to zero range |
---|
22 | (i.e. zero energy). Of course, it is possible for the user to create and |
---|
23 | register a process that kills particles below a certain energy or range; |
---|
24 | this is however <span class="bold"><strong>NOT</strong></span> provided by default |
---|
25 | in Geant4. So there's <span class="bold"><strong>NO</strong></span> "tracking cut". |
---|
26 | For example, suppose a particle that is nearing zero energy will at some |
---|
27 | point be proposed by its Ionisation process to undergo one final step, |
---|
28 | from its current energy down to zero energy. This is still only a |
---|
29 | proposal. If during this step the particle crosses a boundary, then the |
---|
30 | transportation will limit the step at a length smaller than the |
---|
31 | Ionisation -- so the particle will still see and cross the relevant |
---|
32 | boundary, and another step will occur on the other side of that boundary. |
---|
33 | In summary the "production threshold" range and its equivalent in energy |
---|
34 | are not utilised as a "tracking cut". A particle is not abandoned by |
---|
35 | Geant4 below a certain range/energy unless the user registers a process |
---|
36 | to do this by him/her-self. |
---|
37 | </p></td></tr></tbody></table></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ch10s04.html"><img src="AllResources/IconsGIF/prev.gif" alt="Prev"></a> </td><td width="20%" align="center"><a accesskey="u" href="ch10.html"><img src="AllResources/IconsGIF/up.gif" alt="Up"></a></td><td width="40%" align="right"> <a accesskey="n" href="ch10s06.html"><img src="AllResources/IconsGIF/next.gif" alt="Next"></a></td></tr><tr><td width="40%" align="left" valign="top">FAQ.4. |
---|
38 | Tracks and steps |
---|
39 | </td><td width="20%" align="center"><a accesskey="h" href="index.html"><img src="AllResources/IconsGIF/home.gif" alt="Home"></a></td><td width="40%" align="right" valign="top"> FAQ.6. |
---|
40 | Visualization |
---|
41 | </td></tr></table></div></body></html> |
---|