| 1 | <html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>4.4. Hits</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="ch04.html" title="Chapter 4. Detector Definition and Response"><link rel="prev" href="ch04s03.html" title="4.3. Electromagnetic Field"><link rel="next" href="ch04s05.html" title="4.5. Digitization"><script language="JavaScript">
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| 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">4.4.
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| 9 | Hits
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| 10 | </th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ch04s03.html"><img src="AllResources/IconsGIF/prev.gif" alt="Prev"></a> </td><th width="60%" align="center">Chapter 4.
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| 11 | Detector Definition and Response
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| 12 | </th><td width="20%" align="right"> <a accesskey="n" href="ch04s05.html"><img src="AllResources/IconsGIF/next.gif" alt="Next"></a></td></tr></table><hr></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="sect.Hits"></a>4.4.
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| 13 | Hits
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| 14 | </h2></div></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="sect.Hits.Hit"></a>4.4.1.
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| 15 | Hit
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| 16 | </h3></div></div></div><p>
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| 17 | A hit is a snapshot of the physical interaction of a track in the
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| 18 | sensitive region of a detector. In it you can store information
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| 19 | associated with a <span class="emphasis"><em>G4Step</em></span> object. This information can be
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| 20 |
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| 21 | </p><div class="itemizedlist"><ul type="disc" compact><li><p>
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| 22 | the position and time of the step,
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| 23 | </p></li><li><p>
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| 24 | the momentum and energy of the track,
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| 25 | </p></li><li><p>
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| 26 | the energy deposition of the step,
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| 27 | </p></li><li><p>
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| 28 | geometrical information,
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| 29 | </p></li></ul></div><p>
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| 30 |
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| 31 | or any combination of the above.
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| 32 | </p><h5><a name="id427822"></a>
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| 33 | G4VHit
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| 34 | </h5><p>
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| 35 | <span class="emphasis"><em>G4VHit</em></span> is an abstract base class which represents a hit.
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| 36 | You must inherit this base class and derive your own concrete hit
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| 37 | class(es). The member data of your concrete hit class can be, and
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| 38 | should be, your choice.
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| 39 | </p><p>
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| 40 | <span class="emphasis"><em>G4VHit</em></span> has two virtual methods, <code class="literal">Draw()</code> and
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| 41 | <code class="literal">Print()</code>. To draw or print out your concrete hits, these
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| 42 | methods should be implemented. How to define the drawing method is
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| 43 | described in <a href="ch08s09.html" title="8.9.
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| 44 | Polylines, Markers and Text
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| 45 | ">Section 8.9</a>.
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| 46 | </p><h5><a name="id427865"></a>
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| 47 | G4THitsCollection
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| 48 | </h5><p>
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| 49 | <span class="emphasis"><em>G4VHit</em></span> is an abstract class from which you derive your
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| 50 | own concrete classes. During the processing of a given event,
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| 51 | represented by a <span class="emphasis"><em>G4Event</em></span> object, many objects of the hit
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| 52 | class will be produced, collected and associated with the event.
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| 53 | Therefore, for each concrete hit class you must also prepare a
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| 54 | concrete class derived from <span class="emphasis"><em>G4VHitsCollection</em></span>, an abstract
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| 55 | class which represents a vector collection of user defined
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| 56 | hits.
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| 57 | </p><p>
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| 58 | <span class="emphasis"><em>G4THitsCollection</em></span> is a template class derived from
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| 59 | <span class="emphasis"><em>G4VHitsCollection</em></span>, and the concrete hit collection class of
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| 60 | a particular <span class="emphasis"><em>G4VHit</em></span> concrete class can be instantiated from
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| 61 | this template class. Each object of a hit collection must have a
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| 62 | unique name for each event.
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| 63 | </p><p>
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| 64 | <span class="emphasis"><em>G4Event</em></span> has a <span class="emphasis"><em>G4HCofThisEvent</em></span> class
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| 65 | object, that is a container class of collections of hits. Hit collections are
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| 66 | stored by their pointers, whose type is that of the base class.
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| 67 | </p><h5><a name="id427918"></a>
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| 68 | An example of a concrete hit class
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| 69 | </h5><p>
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| 70 | <a href="ch04s04.html#programlist_Hits_1" title="Example 4.14.
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| 71 | An example of a concrete hit class.
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| 72 | ">Example 4.14</a> shows an example of a concrete hit class.
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| 73 |
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| 74 | </p><div class="example"><a name="programlist_Hits_1"></a><p class="title"><b>Example 4.14.
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| 75 | An example of a concrete hit class.
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| 76 | </b></p><div class="example-contents"><pre class="programlisting">
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| 77 | #ifndef ExN04TrackerHit_h
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| 78 | #define ExN04TrackerHit_h 1
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| 79 |
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| 80 | #include "G4VHit.hh"
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| 81 | #include "G4THitsCollection.hh"
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| 82 | #include "G4Allocator.hh"
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| 83 | #include "G4ThreeVector.hh"
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| 84 |
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| 85 | class ExN04TrackerHit : public G4VHit
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| 86 | {
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| 87 | public:
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| 88 |
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| 89 | ExN04TrackerHit();
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| 90 | ~ExN04TrackerHit();
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| 91 | ExN04TrackerHit(const ExN04TrackerHit &right);
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| 92 | const ExN04TrackerHit& operator=(const ExN04TrackerHit &right);
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| 93 | int operator==(const ExN04TrackerHit &right) const;
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| 94 |
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| 95 | inline void * operator new(size_t);
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| 96 | inline void operator delete(void *aHit);
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| 97 |
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| 98 | void Draw() const;
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| 99 | void Print() const;
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| 100 |
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| 101 | private:
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| 102 | G4double edep;
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| 103 | G4ThreeVector pos;
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| 104 |
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| 105 | public:
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| 106 | inline void SetEdep(G4double de)
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| 107 | { edep = de; }
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| 108 | inline G4double GetEdep() const
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| 109 | { return edep; }
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| 110 | inline void SetPos(G4ThreeVector xyz)
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| 111 | { pos = xyz; }
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| 112 | inline G4ThreeVector GetPos() const
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| 113 | { return pos; }
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| 114 |
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| 115 | };
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| 116 |
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| 117 | typedef G4THitsCollection<ExN04TrackerHit> ExN04TrackerHitsCollection;
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| 118 |
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| 119 | extern G4Allocator<ExN04TrackerHit> ExN04TrackerHitAllocator;
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| 120 |
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| 121 | inline void* ExN04TrackerHit::operator new(size_t)
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| 122 | {
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| 123 | void *aHit;
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| 124 | aHit = (void *) ExN04TrackerHitAllocator.MallocSingle();
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| 125 | return aHit;
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| 126 | }
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| 127 |
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| 128 | inline void ExN04TrackerHit::operator delete(void *aHit)
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| 129 | {
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| 130 | ExN04TrackerHitAllocator.FreeSingle((ExN04TrackerHit*) aHit);
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| 131 | }
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| 132 |
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| 133 | #endif
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| 134 | </pre></div></div><p><br class="example-break">
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| 135 | </p><p>
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| 136 | <span class="emphasis"><em>G4Allocator</em></span> is a class for fast allocation of objects to
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| 137 | the heap through the paging mechanism. For details of
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| 138 | <span class="emphasis"><em>G4Allocator</em></span>, refer to <a href="ch03s02.html#sect.GeneManage" title="3.2.4.
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| 139 | General management classes
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| 140 | ">Section 3.2.4</a>.
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| 141 | Use of <span class="emphasis"><em>G4Allocator</em></span>
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| 142 | is not mandatory, but it is recommended, especially for users who
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| 143 | are not familiar with the C++ memory allocation mechanism or
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| 144 | alternative tools of memory allocation. On the other hand, note
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| 145 | that <span class="emphasis"><em>G4Allocator</em></span> is to be used
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| 146 | <span class="bold"><strong>only</strong></span> for the concrete
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| 147 | class that is <span class="bold"><strong>not</strong></span> used as a base
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| 148 | class of any other classes.
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| 149 | For example, do <span class="bold"><strong>not</strong></span> use the
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| 150 | <span class="emphasis"><em>G4Trajectory</em></span> class as a
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| 151 | base class for a customized trajectory class, since
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| 152 | <span class="emphasis"><em>G4Trajectory</em></span> uses <span class="emphasis"><em>G4Allocator</em></span>.
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| 153 | </p><h5><a name="id428028"></a>
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| 154 | G4THitsMap
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| 155 | </h5><p>
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| 156 | <span class="emphasis"><em>G4THitsMap</em></span> is an alternative to
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| 157 | <span class="emphasis"><em>G4THitsCollection</em></span>.
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| 158 | <span class="emphasis"><em>G4THitsMap</em></span> does not demand <span class="emphasis"><em>G4VHit</em></span>,
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| 159 | but instead any variable which can be mapped with an integer key. Typically the key
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| 160 | is a copy number of the volume, and the mapped value could for
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| 161 | example be a double, such as the energy deposition in a volume.
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| 162 | <span class="emphasis"><em>G4THitsMap</em></span> is convenient for applications which do not need
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| 163 | to output event-by-event data but instead just accumulate them. All
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| 164 | the <span class="emphasis"><em>G4VPrimitiveScorer</em></span> classes discussed in
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| 165 | <a href="ch04s04.html#sect.Hits.G4Multi" title="4.4.5.
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| 166 | G4MultiFunctionalDetector and
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| 167 | G4VPrimitiveScorer
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| 168 | ">Section 4.4.5</a> use <span class="emphasis"><em>G4THitsMap</em></span>.
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| 169 | </p><p>
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| 170 | <span class="emphasis"><em>G4THitsMap</em></span> is derived from the
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| 171 | <span class="emphasis"><em>G4VHitsCollection</em></span>
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| 172 | abstract base class and all objects of this class are also stored
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| 173 | in <span class="emphasis"><em>G4HCofThisEvent</em></span> at the end of an event. How to access a
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| 174 | <span class="emphasis"><em>G4THitsMap</em></span> object is discussed in the
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| 175 | following section (<a href="ch04s04.html#sect.Hits.G4Multi" title="4.4.5.
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| 176 | G4MultiFunctionalDetector and
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| 177 | G4VPrimitiveScorer
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| 178 | ">Section 4.4.5</a>).
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| 179 | </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="sect.Hits.SensDet"></a>4.4.2.
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| 180 | Sensitive detector
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| 181 | </h3></div></div></div><h5><a name="id428112"></a>
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| 182 | G4VSensitiveDetector
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| 183 | </h5><p>
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| 184 | <span class="emphasis"><em>G4VSensitiveDetector</em></span> is an abstract base class which
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| 185 | represents a detector. The principal mandate of a sensitive
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| 186 | detector is the construction of hit objects using information from
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| 187 | steps along a particle track. The <code class="literal">ProcessHits()</code> method of
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| 188 | <span class="emphasis"><em>G4VSensitiveDetector</em></span> performs this task using
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| 189 | <span class="emphasis"><em>G4Step</em></span>
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| 190 | objects as input. In the case of a "Readout" geometry (see
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| 191 | <a href="ch04s04.html#sect.Hits.ReadGeom" title="4.4.3.
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| 192 | Readout geometry
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| 193 | ">Section 4.4.3</a>), objects of the
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| 194 | <span class="emphasis"><em>G4TouchableHistory</em></span> class may be used as an optional input.
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| 195 | </p><p>
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| 196 | Your concrete detector class should be instantiated with the
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| 197 | unique name of your detector. The name can be associated with one
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| 198 | or more global names with "/" as a delimiter for categorizing your
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| 199 | detectors. For example
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| 200 |
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| 201 | </p><div class="informalexample"><pre class="programlisting">
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| 202 | myEMcal = new MyEMcal("/myDet/myCal/myEMcal");
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| 203 | </pre></div><p>
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| 204 |
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| 205 | where <code class="literal">myEMcal</code> is the name of your detector. The pointer to
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| 206 | your sensitive detector must be set to one or more
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| 207 | <span class="emphasis"><em>G4LogicalVolume</em></span> objects to set the sensitivity of these
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| 208 | volumes. The pointer should also be registered to
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| 209 | <span class="emphasis"><em>G4SDManager</em></span>, as described in
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| 210 | <a href="ch04s04.html#sect.Hits.G4SDMan" title="4.4.4.
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| 211 | G4SDManager
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| 212 | ">Section 4.4.4</a>.
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| 213 | </p><p>
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| 214 | <span class="emphasis"><em>G4VSensitiveDetector</em></span> has three major virtual methods.
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| 215 |
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| 216 | </p><div class="variablelist"><p class="title"><b></b></p><dl><dt><span class="term">
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| 217 | <code class="literal">ProcessHits()</code>
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| 218 | </span></dt><dd><p>
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| 219 | This method is invoked by <span class="emphasis"><em>G4SteppingManager</em></span> when a step
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| 220 | is composed in the <span class="emphasis"><em>G4LogicalVolume</em></span> which has the pointer
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| 221 | to this sensitive detector. The first argument of this method is a
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| 222 | <span class="emphasis"><em>G4Step</em></span> object of the current step. The second argument is a
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| 223 | <span class="emphasis"><em>G4TouchableHistory</em></span> object for the ``Readout geometry''
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| 224 | described in the next section. The second argument is <code class="literal">NULL</code>
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| 225 | if ``Readout geometry'' is not assigned to this sensitive detector.
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| 226 | In this method, one or more <span class="emphasis"><em>G4VHit</em></span> objects should be
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| 227 | constructed if the current step is meaningful for your
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| 228 | detector.
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| 229 | </p></dd><dt><span class="term">
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| 230 | <code class="literal">Initialize()</code>
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| 231 | </span></dt><dd><p>
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| 232 | This method is invoked at the beginning of each event. The
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| 233 | argument of this method is an object of the <span class="emphasis"><em>G4HCofThisEvent</em></span>
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| 234 | class. Hit collections, where hits produced in this particular
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| 235 | event are stored, can be associated with the <span class="emphasis"><em>G4HCofThisEvent</em></span>
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| 236 | object in this method. The hit collections associated with the
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| 237 | <span class="emphasis"><em>G4HCofThisEvent</em></span> object during this method can be used for
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| 238 | ``during the event processing'' digitization.
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| 239 | </p></dd><dt><span class="term">
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| 240 | <code class="literal">EndOfEvent()</code>
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| 241 | </span></dt><dd><p>
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| 242 | This method is invoked at the end of each event. The argument
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| 243 | of this method is the same object as the previous method. Hit
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| 244 | collections occasionally created in your sensitive detector can be
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| 245 | associated with the <span class="emphasis"><em>G4HCofThisEvent</em></span> object.
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| 246 | </p></dd></dl></div><p>
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| 247 | </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="sect.Hits.ReadGeom"></a>4.4.3.
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| 248 | Readout geometry
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| 249 | </h3></div></div></div><p>
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| 250 | This section describes how a ``Readout geometry'' can be defined. A
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| 251 | Readout geometry is a virtual, parallel geometry for obtaining the
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| 252 | channel number.
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| 253 | </p><p>
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| 254 | As an example, the accordion calorimeter of <span class="bold"><strong>ATLAS</strong></span>
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| 255 | has a complicated tracking geometry, however the readout can be done by
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| 256 | simple cylindrical sectors divided by theta, phi, and depth. Tracks
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| 257 | will be traced in the tracking geometry, the ``real'' one, and the
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| 258 | sensitive detector will have its own readout geometry Geant4 will
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| 259 | message to find to which ``readout'' cell the current hit
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| 260 | belongs.
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| 261 |
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| 262 | </p><div class="figure"><a name="fig.Hits_1"></a><div class="figure-contents"><div class="mediaobject" align="center"><img src="./AllResources/Detector/hit.src/RO.gif" align="middle" alt="Association of tracking and readout geometry."></div></div><p class="title"><b>Figure 4.8.
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| 263 | Association of tracking and readout geometry.
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| 264 | </b></p></div><p><br class="figure-break">
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| 265 | </p><p>
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| 266 | <a href="ch04s04.html#fig.Hits_1" title="Figure 4.8.
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| 267 | Association of tracking and readout geometry.
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| 268 | ">Figure 4.8</a> shows how this association is done in Geant4.
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| 269 | The first step is to associate a sensitive detector to a volume of the
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| 270 | tracking geometry, in the usual way (see
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| 271 | <a href="ch04s04.html#sect.Hits.SensDet" title="4.4.2.
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| 272 | Sensitive detector
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| 273 | ">Section 4.4.2</a>). The next step is to associate your
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| 274 | <span class="emphasis"><em>G4VReadoutGeometry</em></span> object to the sensitive detector.
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| 275 | </p><p>
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| 276 | At tracking time, the base class <span class="emphasis"><em>G4VReadoutGeometry</em></span> will
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| 277 | provide to your sensitive detector code the
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| 278 | <span class="emphasis"><em>G4TouchableHistory</em></span> in the Readout geometry at the beginning
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| 279 | of the step position (position of <span class="emphasis"><em>PreStepPoint</em></span> of
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| 280 | <span class="emphasis"><em>G4Step</em></span>) and at this position only.
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| 281 | </p><p>
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| 282 | This <span class="emphasis"><em>G4TouchableHistory</em></span> is given to your sensitive
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| 283 | detector code through the <span class="emphasis"><em>G4VSensitiveDetector</em></span> virtual
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| 284 | method:
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| 285 |
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| 286 | </p><div class="informalexample"><pre class="programlisting">
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| 287 | G4bool processHits(G4Step* aStep, G4TouchableHistory* ROhist);
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| 288 | </pre></div><p>
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| 289 |
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| 290 | by the <code class="literal">ROhist</code> argument.
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| 291 | </p><p>
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| 292 | Thus, you will be able to use information from both the
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| 293 | <span class="emphasis"><em>G4Step</em></span> and the <span class="emphasis"><em>G4TouchableHistory</em></span>
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| 294 | coming from your
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| 295 | Readout geometry. Note that since the association is done through a
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| 296 | sensitive detector object, it is perfectly possible to have several
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| 297 | Readout geometries in parallel.
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| 298 | </p><h5><a name="id428454"></a>
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| 299 | Definition of a virtual geometry setup
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| 300 | </h5><p>
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| 301 | The base class for the implementation of a Readout geometry is
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| 302 | <span class="emphasis"><em>G4VReadoutGeometry</em></span>. This class has a single pure virtual
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| 303 | protected method:
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| 304 |
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| 305 | </p><div class="informalexample"><pre class="programlisting">
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| 306 | virtual G4VPhysicalVolume* build() = 0;
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| 307 | </pre></div><p>
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| 308 |
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| 309 | which you must override in your concrete class. The
|
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| 310 | <span class="emphasis"><em>G4VPhysicalVolume</em></span> pointer you will have to return is of the
|
|---|
| 311 | physical world of the Readout geometry.
|
|---|
| 312 | </p><p>
|
|---|
| 313 | The step by step procedure for constructing a Readout geometry is:
|
|---|
| 314 |
|
|---|
| 315 | </p><div class="itemizedlist"><ul type="disc" compact><li><p>
|
|---|
| 316 | inherit from <span class="emphasis"><em>G4VReadoutGeometry</em></span> to define a
|
|---|
| 317 | <span class="emphasis"><em>MyROGeom</em></span> class;
|
|---|
| 318 | </p></li><li><p>
|
|---|
| 319 | implement the Readout geometry in the <code class="literal">build()</code> method,
|
|---|
| 320 | returning the physical world of this geometry.
|
|---|
| 321 | </p><p>
|
|---|
| 322 | The world is specified in the same way as for the detector
|
|---|
| 323 | construction: a physical volume with no mother. The axis system of
|
|---|
| 324 | this world is the same as the one of the world for tracking.
|
|---|
| 325 | </p><p>
|
|---|
| 326 | </p><p>
|
|---|
| 327 | In this geometry you need to declare the sensitive parts in the
|
|---|
| 328 | same way as in the tracking geometry: by setting a
|
|---|
| 329 | non-<code class="literal">NULL</code> <span class="emphasis"><em>G4VSensitiveDetector</em></span>
|
|---|
| 330 | pointer in, say, the
|
|---|
| 331 | relevant <span class="emphasis"><em>G4LogicalVolume</em></span> objects. This sensitive class needs
|
|---|
| 332 | to be there, but will not be used.
|
|---|
| 333 | </p><p>
|
|---|
| 334 | </p><p>
|
|---|
| 335 | You will also need to assign well defined materials to the
|
|---|
| 336 | volumes you place in this geometry, but these materials are
|
|---|
| 337 | irrelevant since they will not be seen by the tracking. It is
|
|---|
| 338 | foreseen to allow the setting of a <code class="literal">NULL</code> pointer in this
|
|---|
| 339 | case of the parallel geometry.
|
|---|
| 340 | </p><p>
|
|---|
| 341 | </p></li><li><p>
|
|---|
| 342 | in the <code class="literal">construct()</code> method of your concrete
|
|---|
| 343 | <span class="emphasis"><em>G4VUserDetectorConstruction</em></span> class:
|
|---|
| 344 | </p><p>
|
|---|
| 345 | </p><div class="itemizedlist"><ul type="circle" compact><li><p>
|
|---|
| 346 | instantiate your Readout geometry:
|
|---|
| 347 | </p><div class="informalexample"><pre class="programlisting">
|
|---|
| 348 | MyROGeom* ROgeom = new MyROGeom("ROName");
|
|---|
| 349 | </pre></div><p>
|
|---|
| 350 | </p></li><li><p>
|
|---|
| 351 | build it:
|
|---|
| 352 | </p><div class="informalexample"><pre class="programlisting">
|
|---|
| 353 | ROgeom->buildROGeometry();
|
|---|
| 354 | </pre></div><p>
|
|---|
| 355 | That will invoke your <code class="literal">build()</code> method.
|
|---|
| 356 | </p></li><li><p>
|
|---|
| 357 | Instantiate the sensitive detector which will receive the
|
|---|
| 358 | <code class="literal">ROGeom</code> pointer, <code class="literal">MySensitive</code>,
|
|---|
| 359 | and add this sensitive to the <span class="emphasis"><em>G4SDManager</em></span>.
|
|---|
| 360 | Associate this sensitive to
|
|---|
| 361 | the volume(s) of the tracking geometry as usual.
|
|---|
| 362 | </p></li><li><p>
|
|---|
| 363 | Associate the sensitive to the Readout geometry:
|
|---|
| 364 | </p><div class="informalexample"><pre class="programlisting">
|
|---|
| 365 | MySensitive->SetROgeometry(ROgeom);
|
|---|
| 366 | </pre></div><p>
|
|---|
| 367 | </p></li></ul></div><p>
|
|---|
| 368 | </p><p>
|
|---|
| 369 | </p></li></ul></div><p>
|
|---|
| 370 | </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="sect.Hits.G4SDMan"></a>4.4.4.
|
|---|
| 371 | G4SDManager
|
|---|
| 372 | </h3></div></div></div><p>
|
|---|
| 373 | <span class="emphasis"><em>G4SDManager</em></span> is the singleton manager class for sensitive
|
|---|
| 374 | detectors.
|
|---|
| 375 | </p><h5><a name="id428671"></a>
|
|---|
| 376 | Activation/inactivation of sensitive detectors
|
|---|
| 377 | </h5><p>
|
|---|
| 378 | The user interface commands <code class="literal">activate</code> and
|
|---|
| 379 | <code class="literal">inactivate</code> are available to control your sensitive
|
|---|
| 380 | detectors. For example:
|
|---|
| 381 |
|
|---|
| 382 | </p><div class="informalexample"><pre class="programlisting">
|
|---|
| 383 | /hits/activate detector_name
|
|---|
| 384 | /hits/inactivate detector_name
|
|---|
| 385 | </pre></div><p>
|
|---|
| 386 |
|
|---|
| 387 | where <code class="literal">detector_name</code> can be the detector name or the
|
|---|
| 388 | category name.
|
|---|
| 389 | </p><p>
|
|---|
| 390 | For example, if your EM calorimeter is named
|
|---|
| 391 |
|
|---|
| 392 | </p><div class="informalexample"><pre class="programlisting">
|
|---|
| 393 | /myDet/myCal/myEMcal
|
|---|
| 394 | /hits/inactivate myCal
|
|---|
| 395 | </pre></div><p>
|
|---|
| 396 |
|
|---|
| 397 | will inactivate all detectors belonging to the <code class="literal">myCal</code>
|
|---|
| 398 | category.
|
|---|
| 399 | </p><h5><a name="id428731"></a>
|
|---|
| 400 | Access to the hit collections
|
|---|
| 401 | </h5><p>Hit collections are accessed for various cases.
|
|---|
| 402 |
|
|---|
| 403 | </p><div class="itemizedlist"><ul type="disc" compact><li><p>
|
|---|
| 404 | Digitization
|
|---|
| 405 | </p></li><li><p>
|
|---|
| 406 | Event filtering in <span class="emphasis"><em>G4VUserStackingAction</em></span>
|
|---|
| 407 | </p></li><li><p>
|
|---|
| 408 | ``End of event'' simple analysis
|
|---|
| 409 | </p></li><li><p>
|
|---|
| 410 | Drawing / printing hits
|
|---|
| 411 | </p></li></ul></div><p>
|
|---|
| 412 | </p><p>
|
|---|
| 413 | The following is an example of how to access the hit collection
|
|---|
| 414 | of a particular concrete type:
|
|---|
| 415 |
|
|---|
| 416 | </p><div class="informalexample"><pre class="programlisting">
|
|---|
| 417 | G4SDManager* fSDM = G4SDManager::GetSDMpointer();
|
|---|
| 418 | G4RunManager* fRM = G4RunManager::GetRunManager();
|
|---|
| 419 | G4int collectionID = fSDM->GetCollectionID("collection_name");
|
|---|
| 420 | const G4Event* currentEvent = fRM->GetCurrentEvent();
|
|---|
| 421 | G4HCofThisEvent* HCofEvent = currentEvent->GetHCofThisEvent();
|
|---|
| 422 | <span class="emphasis"><em>MyHitsCollection</em></span>* myCollection = (<span class="emphasis"><em>MyHitsCollection</em></span>*)(HC0fEvent->GetHC(collectionID));
|
|---|
| 423 | </pre></div><p>
|
|---|
| 424 | </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="sect.Hits.G4Multi"></a>4.4.5.
|
|---|
| 425 | <span class="emphasis"><em>G4MultiFunctionalDetector</em></span> and
|
|---|
| 426 | <span class="emphasis"><em>G4VPrimitiveScorer</em></span>
|
|---|
| 427 | </h3></div></div></div><p>
|
|---|
| 428 | <span class="emphasis"><em>G4MultiFunctionalDetector</em></span> is a concrete class derived from
|
|---|
| 429 | <span class="emphasis"><em>G4VSensitiveDetector</em></span>. Instead of implementing a
|
|---|
| 430 | user-specific detector class, <span class="emphasis"><em>G4MultiFunctionalDetector</em></span>
|
|---|
| 431 | allows the user to register <span class="emphasis"><em>G4VPrimitiveScorer</em></span> classes to
|
|---|
| 432 | build up the sensitivity. <span class="emphasis"><em>G4MultiFunctionalDetector</em></span> should
|
|---|
| 433 | be instantiated in the users detector construction with its unique
|
|---|
| 434 | name and should be assigned to one or more <span class="emphasis"><em>G4LogicalVolume</em></span>s.
|
|---|
| 435 | </p><p>
|
|---|
| 436 | <span class="emphasis"><em>G4VPrimitiveScorer</em></span> is an abstract base class representing
|
|---|
| 437 | a class to be registered to <span class="emphasis"><em>G4MultiFunctionalDetector</em></span> that
|
|---|
| 438 | creates a <span class="emphasis"><em>G4THitsMap</em></span> object of one physics quantity for an
|
|---|
| 439 | event. Geant4 provides many concrete primitive scorer classes
|
|---|
| 440 | listed in <a href="ch04s04.html#sect.Hits.G4VPrim" title="4.4.6.
|
|---|
| 441 | Concrete classes of G4VPrimitiveScorer
|
|---|
| 442 | ">Section 4.4.6</a>, and the user can
|
|---|
| 443 | also implement his/her own primitive scorers. Each primitive scorer
|
|---|
| 444 | object must be instantiated with a name that must be unique among
|
|---|
| 445 | primitive scorers registered in a <span class="emphasis"><em>G4MultiFunctionalDetector</em></span>.
|
|---|
| 446 | Please note that a primitive scorer object must <span class="bold"><strong>not</strong></span> be
|
|---|
| 447 | shared by more than one <span class="emphasis"><em>G4MultiFunctionalDetector</em></span>
|
|---|
| 448 | object.
|
|---|
| 449 | </p><p>As mentioned in <a href="ch04s04.html#sect.Hits.Hit" title="4.4.1.
|
|---|
| 450 | Hit
|
|---|
| 451 | ">Section 4.4.1</a>,
|
|---|
| 452 | each <span class="emphasis"><em>G4VPrimitiveScorer</em></span> generates one
|
|---|
| 453 | <span class="emphasis"><em>G4THitsMap</em></span> object
|
|---|
| 454 | per event. The name of the map object is the same as the name of
|
|---|
| 455 | the primitive scorer. Each of the concrete primitive scorers listed
|
|---|
| 456 | in <a href="ch04s04.html#sect.Hits.G4VPrim" title="4.4.6.
|
|---|
| 457 | Concrete classes of G4VPrimitiveScorer
|
|---|
| 458 | ">Section 4.4.6</a> generates a
|
|---|
| 459 | <span class="emphasis"><em>G4THitsMap<G4double></em></span> that maps a
|
|---|
| 460 | <span class="emphasis"><em>G4double</em></span> value
|
|---|
| 461 | to its key integer number. By default, the key is taken as the copy
|
|---|
| 462 | number of the <span class="emphasis"><em>G4LogicalVolume</em></span> to which
|
|---|
| 463 | <span class="emphasis"><em>G4MultiFunctionalDetector</em></span> is assigned. In case the logical
|
|---|
| 464 | volume is uniquely placed in its mother volume and the mother is
|
|---|
| 465 | replicated, the copy number of its mother volume can be taken by
|
|---|
| 466 | setting the second argument of the <span class="emphasis"><em>G4VPrimitiveScorer</em></span>
|
|---|
| 467 | constructor, "<span class="emphasis"><em>depth</em></span>" to 1, i.e. one level up. Furthermore,
|
|---|
| 468 | in case the key must consider more than one copy number of a
|
|---|
| 469 | different geometry hierarchy, the user can derive his/her own
|
|---|
| 470 | primitive scorer from the provided concrete class and implement the
|
|---|
| 471 | <span class="emphasis"><em>GetIndex(G4Step*)</em></span> virtual method to return the unique
|
|---|
| 472 | key.
|
|---|
| 473 | </p><p>
|
|---|
| 474 | <a href="ch04s04.html#programlist_Hits_2" title="Example 4.15.
|
|---|
| 475 | An example of defining primitive sensitivity classes taken from
|
|---|
| 476 | ExN07DetectorConstruction.
|
|---|
| 477 | ">Example 4.15</a> shows an example of primitive sensitivity
|
|---|
| 478 | class definitions.
|
|---|
| 479 |
|
|---|
| 480 | </p><div class="example"><a name="programlist_Hits_2"></a><p class="title"><b>Example 4.15.
|
|---|
| 481 | An example of defining primitive sensitivity classes taken from
|
|---|
| 482 | <span class="emphasis"><em>ExN07DetectorConstruction</em></span>.
|
|---|
| 483 | </b></p><div class="example-contents"><pre class="programlisting">
|
|---|
| 484 | void ExN07DetectorConstruction::SetupDetectors()
|
|---|
| 485 | {
|
|---|
| 486 | G4String filterName, particleName;
|
|---|
| 487 |
|
|---|
| 488 | G4SDParticleFilter* gammaFilter =
|
|---|
| 489 | new G4SDParticleFilter(filterName="gammaFilter",particleName="gamma");
|
|---|
| 490 | G4SDParticleFilter* electronFilter =
|
|---|
| 491 | new G4SDParticleFilter(filterName="electronFilter",particleName="e-");
|
|---|
| 492 | G4SDParticleFilter* positronFilter =
|
|---|
| 493 | new G4SDParticleFilter(filterName="positronFilter",particleName="e+");
|
|---|
| 494 | G4SDParticleFilter* epFilter = new G4SDParticleFilter(filterName="epFilter");
|
|---|
| 495 | epFilter->add(particleName="e-");
|
|---|
| 496 | epFilter->add(particleName="e+");
|
|---|
| 497 |
|
|---|
| 498 |
|
|---|
| 499 | for(G4int i=0;i<3;i++)
|
|---|
| 500 | {
|
|---|
| 501 | for(G4int j=0;j<2;j++)
|
|---|
| 502 | {
|
|---|
| 503 | // Loop counter j = 0 : absorber
|
|---|
| 504 | // = 1 : gap
|
|---|
| 505 | G4String detName = calName[i];
|
|---|
| 506 | if(j==0)
|
|---|
| 507 | { detName += "_abs"; }
|
|---|
| 508 | else
|
|---|
| 509 | { detName += "_gap"; }
|
|---|
| 510 | G4MultiFunctionalDetector* det = new G4MultiFunctionalDetector(detName);
|
|---|
| 511 |
|
|---|
| 512 | // The second argument in each primitive means the "level" of geometrical hierarchy,
|
|---|
| 513 | // the copy number of that level is used as the key of the G4THitsMap.
|
|---|
| 514 | // For absorber (j = 0), the copy number of its own physical volume is used.
|
|---|
| 515 | // For gap (j = 1), the copy number of its mother physical volume is used, since there
|
|---|
| 516 | // is only one physical volume of gap is placed with respect to its mother.
|
|---|
| 517 | G4VPrimitiveScorer* primitive;
|
|---|
| 518 | primitive = new G4PSEnergyDeposit("eDep",j);
|
|---|
| 519 | det->RegisterPrimitive(primitive);
|
|---|
| 520 | primitive = new G4PSNofSecondary("nGamma",j);
|
|---|
| 521 | primitive->SetFilter(gammaFilter);
|
|---|
| 522 | det->RegisterPrimitive(primitive);
|
|---|
| 523 | primitive = new G4PSNofSecondary("nElectron",j);
|
|---|
| 524 | primitive->SetFilter(electronFilter);
|
|---|
| 525 | det->RegisterPrimitive(primitive);
|
|---|
| 526 | primitive = new G4PSNofSecondary("nPositron",j);
|
|---|
| 527 | primitive->SetFilter(positronFilter);
|
|---|
| 528 | det->RegisterPrimitive(primitive);
|
|---|
| 529 | primitive = new G4PSMinKinEAtGeneration("minEkinGamma",j);
|
|---|
| 530 | primitive->SetFilter(gammaFilter);
|
|---|
| 531 | det->RegisterPrimitive(primitive);
|
|---|
| 532 | primitive = new G4PSMinKinEAtGeneration("minEkinElectron",j);
|
|---|
| 533 | primitive->SetFilter(electronFilter);
|
|---|
| 534 | det->RegisterPrimitive(primitive);
|
|---|
| 535 | primitive = new G4PSMinKinEAtGeneration("minEkinPositron",j);
|
|---|
| 536 | primitive->SetFilter(positronFilter);
|
|---|
| 537 | det->RegisterPrimitive(primitive);
|
|---|
| 538 | primitive = new G4PSTrackLength("trackLength",j);
|
|---|
| 539 | primitive->SetFilter(epFilter);
|
|---|
| 540 | det->RegisterPrimitive(primitive);
|
|---|
| 541 | primitive = new G4PSNofStep("nStep",j);
|
|---|
| 542 | primitive->SetFilter(epFilter);
|
|---|
| 543 | det->RegisterPrimitive(primitive);
|
|---|
| 544 |
|
|---|
| 545 | G4SDManager::GetSDMpointer()->AddNewDetector(det);
|
|---|
| 546 | if(j==0)
|
|---|
| 547 | { layerLogical[i]->SetSensitiveDetector(det); }
|
|---|
| 548 | else
|
|---|
| 549 | { gapLogical[i]->SetSensitiveDetector(det); }
|
|---|
| 550 | }
|
|---|
| 551 | }
|
|---|
| 552 | }
|
|---|
| 553 | </pre></div></div><p><br class="example-break">
|
|---|
| 554 | </p><p>
|
|---|
| 555 | Each <span class="emphasis"><em>G4THitsMap</em></span> object can be accessed from
|
|---|
| 556 | <span class="emphasis"><em>G4HCofThisEvent</em></span> with a unique collection ID number. This ID
|
|---|
| 557 | number can be obtained from <span class="emphasis"><em>G4SDManager::GetCollectionID()</em></span>
|
|---|
| 558 | with a name of <span class="emphasis"><em>G4MultiFunctionalDetector</em></span> and
|
|---|
| 559 | <span class="emphasis"><em>G4VPrimitiveScorer</em></span> connected with a slush ("/").
|
|---|
| 560 | <span class="emphasis"><em>G4THitsMap</em></span> has a [] operator taking the key value as an
|
|---|
| 561 | argument and returning <span class="bold"><strong>the pointer</strong></span> of the value.
|
|---|
| 562 | Please note that the [] operator returns
|
|---|
| 563 | <span class="bold"><strong>the pointer</strong></span> of the value. If
|
|---|
| 564 | you get zero from the [] operator, it does <span class="bold"><strong>not</strong></span> mean the
|
|---|
| 565 | value is zero, but that the provided key does not exist. The value
|
|---|
| 566 | itself is accessible with an astarisk ("*"). It is advised to check
|
|---|
| 567 | the validity of the returned pointer before accessing the value.
|
|---|
| 568 | <span class="emphasis"><em>G4THitsMap</em></span> also has a += operator in order to accumulate
|
|---|
| 569 | event data into run data. <a href="ch04s04.html#programlist_Hits_3" title="Example 4.16.
|
|---|
| 570 | An example of accessing to G4THitsMap objects.
|
|---|
| 571 | ">Example 4.16</a> shows the use of
|
|---|
| 572 | <span class="emphasis"><em>G4THitsMap</em></span>.
|
|---|
| 573 |
|
|---|
| 574 | </p><div class="example"><a name="programlist_Hits_3"></a><p class="title"><b>Example 4.16.
|
|---|
| 575 | An example of accessing to <span class="emphasis"><em>G4THitsMap</em></span> objects.
|
|---|
| 576 | </b></p><div class="example-contents"><pre class="programlisting">
|
|---|
| 577 | #include "ExN07Run.hh"
|
|---|
| 578 | #include "G4Event.hh"
|
|---|
| 579 | #include "G4HCofThisEvent.hh"
|
|---|
| 580 | #include "G4SDManager.hh"
|
|---|
| 581 |
|
|---|
| 582 | ExN07Run::ExN07Run()
|
|---|
| 583 | {
|
|---|
| 584 | G4String detName[6] = {"Calor-A_abs","Calor-A_gap","Calor-B_abs","Calor-B_gap",
|
|---|
| 585 | "Calor-C_abs","Calor-C_gap"};
|
|---|
| 586 | G4String primNameSum[6] = {"eDep","nGamma","nElectron","nPositron","trackLength","nStep"};
|
|---|
| 587 | G4String primNameMin[3] = {"minEkinGamma","minEkinElectron","minEkinPositron"};
|
|---|
| 588 |
|
|---|
| 589 | G4SDManager* SDMan = G4SDManager::GetSDMpointer();
|
|---|
| 590 | G4String fullName;
|
|---|
| 591 | for(size_t i=0;i<6;i++)
|
|---|
| 592 | {
|
|---|
| 593 | for(size_t j=0;j<6;j++)
|
|---|
| 594 | {
|
|---|
| 595 | fullName = detName[i]+"/"+primNameSum[j];
|
|---|
| 596 | colIDSum[i][j] = SDMan->GetCollectionID(fullName);
|
|---|
| 597 | }
|
|---|
| 598 | for(size_t k=0;k<3;k++)
|
|---|
| 599 | {
|
|---|
| 600 | fullName = detName[i]+"/"+primNameMin[k];
|
|---|
| 601 | colIDMin[i][k] = SDMan->GetCollectionID(fullName);
|
|---|
| 602 | }
|
|---|
| 603 | }
|
|---|
| 604 | }
|
|---|
| 605 |
|
|---|
| 606 |
|
|---|
| 607 | void ExN07Run::RecordEvent(const G4Event* evt)
|
|---|
| 608 | {
|
|---|
| 609 | G4HCofThisEvent* HCE = evt->GetHCofThisEvent();
|
|---|
| 610 | if(!HCE) return;
|
|---|
| 611 | numberOfEvent++;
|
|---|
| 612 | for(size_t i=0;i<6;i++)
|
|---|
| 613 | {
|
|---|
| 614 | for(size_t j=0;j<6;j++)
|
|---|
| 615 | {
|
|---|
| 616 | G4THitsMap<G4double>* evtMap = (G4THitsMap<G4double>*)(HCE->GetHC(colIDSum[i][j]));
|
|---|
| 617 | mapSum[i][j] += *evtMap;
|
|---|
| 618 | }
|
|---|
| 619 | for(size_t k=0;k<3;k++)
|
|---|
| 620 | {
|
|---|
| 621 | G4THitsMap<G4double>* evtMap = (G4THitsMap<G4double>*)(HCE->GetHC(colIDMin[i][k]));
|
|---|
| 622 | std::map<G4int,G4double*>::iterator itr = evtMap->GetMap()->begin();
|
|---|
| 623 | for(; itr != evtMap->GetMap()->end(); itr++)
|
|---|
| 624 | {
|
|---|
| 625 | G4int key = (itr->first);
|
|---|
| 626 | G4double val = *(itr->second);
|
|---|
| 627 | G4double* mapP = mapMin[i][k][key];
|
|---|
| 628 | if( mapP && (val>*mapP) ) continue;
|
|---|
| 629 | mapMin[i][k].set(key,val);
|
|---|
| 630 | }
|
|---|
| 631 | }
|
|---|
| 632 | }
|
|---|
| 633 | }
|
|---|
| 634 | </pre></div></div><p><br class="example-break">
|
|---|
| 635 | </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="sect.Hits.G4VPrim"></a>4.4.6.
|
|---|
| 636 | Concrete classes of <span class="emphasis"><em>G4VPrimitiveScorer</em></span>
|
|---|
| 637 | </h3></div></div></div><p>
|
|---|
| 638 | With Geant4 version 8.0, several concrete primitive scorer classes
|
|---|
| 639 | are provided, all of which are derived from the
|
|---|
| 640 | <span class="emphasis"><em>G4VPrimitiveScorer</em></span> abstract base class and which are to be
|
|---|
| 641 | registered to <span class="emphasis"><em>G4MultiFunctionalDetector</em></span>. Each of them
|
|---|
| 642 | contains one <span class="emphasis"><em>G4THitsMap</em></span> object and scores a simple double
|
|---|
| 643 | value for each key.
|
|---|
| 644 | </p><h5><a name="id429128"></a>
|
|---|
| 645 | Track length scorers
|
|---|
| 646 | </h5><p>
|
|---|
| 647 | </p><div class="variablelist"><p class="title"><b></b></p><dl><dt><span class="term">
|
|---|
| 648 | G4PSTrackLength
|
|---|
| 649 | </span></dt><dd><p>
|
|---|
| 650 | The track length is defined as the sum of step lengths of the
|
|---|
| 651 | particles inside the cell. Bt default, the track weight is not
|
|---|
| 652 | taken into account, but could be used as a multiplier of each step
|
|---|
| 653 | length if the <span class="emphasis"><em>Weighted()</em></span> method of this class object is
|
|---|
| 654 | invoked.
|
|---|
| 655 | </p></dd><dt><span class="term">
|
|---|
| 656 | G4PSPassageTrackLength
|
|---|
| 657 | </span></dt><dd><p>
|
|---|
| 658 | The passage track length is the same as the track length in
|
|---|
| 659 | <span class="emphasis"><em>G4PSTrackLength</em></span>, except that only tracks which pass
|
|---|
| 660 | through the volume are taken into account. It means newly-generated or
|
|---|
| 661 | stopped tracks inside the cell are excluded from the calculation.
|
|---|
| 662 | By default, the track weight is not taken into account, but could
|
|---|
| 663 | be used as a multiplier of each step length if the
|
|---|
| 664 | <span class="emphasis"><em>Weighted()</em></span> method of this class object is invoked.
|
|---|
| 665 | </p></dd></dl></div><p>
|
|---|
| 666 | </p><h5><a name="id429183"></a>
|
|---|
| 667 | <span class="bold"><strong>Deposited energy scorers</strong></span>
|
|---|
| 668 | </h5><p>
|
|---|
| 669 | </p><div class="variablelist"><p class="title"><b></b></p><dl><dt><span class="term">
|
|---|
| 670 | G4PSEnergyDeposit
|
|---|
| 671 | </span></dt><dd><p>
|
|---|
| 672 | This scorer stores a sum of particles' energy deposits at each
|
|---|
| 673 | step in the cell. The particle weight is multiplied at each
|
|---|
| 674 | step.
|
|---|
| 675 | </p></dd><dt><span class="term">
|
|---|
| 676 | G4PSDoseDeposit
|
|---|
| 677 | </span></dt><dd><p>
|
|---|
| 678 | In some cases, dose is a more convenient way to evaluate the
|
|---|
| 679 | effect of energy deposit in a cell than simple deposited energy.
|
|---|
| 680 | The dose deposit is defined by the sum of energy deposits at each
|
|---|
| 681 | step in a cell divided by the mass of the cell. The mass is
|
|---|
| 682 | calculated from the density and volume of the cell taken from the
|
|---|
| 683 | methods of <span class="emphasis"><em>G4VSolid</em></span> and
|
|---|
| 684 | <span class="emphasis"><em>G4LogicalVolume</em></span>. The particle
|
|---|
| 685 | weight is multiplied at each step.
|
|---|
| 686 | </p></dd></dl></div><p>
|
|---|
| 687 | </p><h5><a name="id429239"></a>
|
|---|
| 688 | <span class="bold"><strong>Current and flux scorers</strong></span>
|
|---|
| 689 | </h5><p>
|
|---|
| 690 | There are two different definitions of a particle's flow for a
|
|---|
| 691 | given geometry. One is a current and the other is a flux. In our
|
|---|
| 692 | scorers, the current is simply defined as the number of particles
|
|---|
| 693 | (with the particle's weight) at a certain surface or volume, while
|
|---|
| 694 | the flux takes the particle's injection angle to the geometry into
|
|---|
| 695 | account. The current and flux are usually defined at a surface, but
|
|---|
| 696 | volume current and volume flux are also provided.
|
|---|
| 697 | </p><p>
|
|---|
| 698 | </p><div class="variablelist"><p class="title"><b></b></p><dl><dt><span class="term">
|
|---|
| 699 | G4PSFlatSurfaceCurrent
|
|---|
| 700 | </span></dt><dd><p>
|
|---|
| 701 | Flat surface current is a surface based scorer. The present
|
|---|
| 702 | implementation is limited to scoring only at the -Z surface of a
|
|---|
| 703 | <span class="emphasis"><em>G4Box</em></span> solid. The quantity is defined by the number
|
|---|
| 704 | of tracks that reach the surface. The user must choose a direction of the
|
|---|
| 705 | particle to be scored. The choices are fCurrent_In, fCurrent_Out,
|
|---|
| 706 | or fCurrent_InOut, one of which must be entered as the second
|
|---|
| 707 | argument of the constructor. Here, fCurrent_In scores incoming
|
|---|
| 708 | particles to the cell, while fCurrent_Out scores only outgoing
|
|---|
| 709 | particles from the cell. fCurrent_InOut scores both directions. The
|
|---|
| 710 | current is multiplied by particle weight and is normalized for a
|
|---|
| 711 | unit area.
|
|---|
| 712 | </p></dd><dt><span class="term">
|
|---|
| 713 | G4PSSphereSurfaceCurrent
|
|---|
| 714 | </span></dt><dd><p>
|
|---|
| 715 | Sphere surface current is a surface based scorer, and similar
|
|---|
| 716 | to the G4PSFlatSurfaceCurrent. The only difference is that the
|
|---|
| 717 | surface is defined at the <span class="bold"><strong>inner surface</strong></span>
|
|---|
| 718 | of a G4Sphere solid.
|
|---|
| 719 | </p></dd><dt><span class="term">
|
|---|
| 720 | G4PSPassageCurrent
|
|---|
| 721 | </span></dt><dd><p>
|
|---|
| 722 | Passage current is a volume-based scorer. The current is
|
|---|
| 723 | defined by the number of tracks that pass through the volume. A
|
|---|
| 724 | particle weight is applied at the exit point. A passage current is
|
|---|
| 725 | defined for a volume.
|
|---|
| 726 | </p></dd><dt><span class="term">
|
|---|
| 727 | G4PSFlatSurfaceFlux
|
|---|
| 728 | </span></dt><dd><p>
|
|---|
| 729 | Flat surface flux is a surface based flux scorer. The surface
|
|---|
| 730 | flux is defined by the number of tracks that reach the surface. The
|
|---|
| 731 | expression of surface flux is given by the sum of W/cos(t)/A, where
|
|---|
| 732 | W, t and A represent particle weight, injection angle of particle
|
|---|
| 733 | with respect to the surface normal, and area of the surface. The
|
|---|
| 734 | user must enter one of the particle directions, fFlux_In,
|
|---|
| 735 | fFlux_Out, or fFlux_InOut in the constructor. Here, fFlux_In scores
|
|---|
| 736 | incoming particles to the cell, while fFlux_Out scores outgoing
|
|---|
| 737 | particles from the cell. fFlux_InOut scores both directions.
|
|---|
| 738 | </p></dd><dt><span class="term">
|
|---|
| 739 | G4PSCellFlux
|
|---|
| 740 | </span></dt><dd><p>
|
|---|
| 741 | Cell flux is a volume based flux scorer. The cell flux is
|
|---|
| 742 | defined by a track length (L) of the particle inside a volume
|
|---|
| 743 | divided by the volume (V) of this cell. The track length is
|
|---|
| 744 | calculated by a sum of the step lengths in the cell. The expression
|
|---|
| 745 | for cell flux is given by the sum of (W*L)/V, where W is a particle
|
|---|
| 746 | weight, and is multiplied by the track length at each step.
|
|---|
| 747 | </p></dd><dt><span class="term">
|
|---|
| 748 | G4PSPassageCellFlux
|
|---|
| 749 | </span></dt><dd><p>
|
|---|
| 750 | Passage cell flux is a volume based scorer similar to
|
|---|
| 751 | <span class="emphasis"><em>G4PSCellFlux</em></span>. The only difference is that tracks
|
|---|
| 752 | which pass through a cell are taken into account. It means generated or
|
|---|
| 753 | stopped tracks inside the volume are excluded from the
|
|---|
| 754 | calculation.
|
|---|
| 755 | </p></dd></dl></div><p>
|
|---|
| 756 | </p><h5><a name="id429373"></a>
|
|---|
| 757 | <span class="bold"><strong>Other scorers</strong></span>
|
|---|
| 758 | </h5><p>
|
|---|
| 759 | </p><div class="variablelist"><p class="title"><b></b></p><dl><dt><span class="term">
|
|---|
| 760 | G4PSMinKinEAtGeneration
|
|---|
| 761 | </span></dt><dd><p>
|
|---|
| 762 | This scorer records the minimum kinetic energy of secondary
|
|---|
| 763 | particles at their production point in the volume in an event. This
|
|---|
| 764 | primitive scorer does not integrate the quantity, but records the
|
|---|
| 765 | minimum quantity.
|
|---|
| 766 | </p></dd><dt><span class="term">
|
|---|
| 767 | G4PSNofSecondary
|
|---|
| 768 | </span></dt><dd><p>
|
|---|
| 769 | This class scores the number of secondary particles generated
|
|---|
| 770 | in the volume. The weight of the secondary track is taken into
|
|---|
| 771 | account.
|
|---|
| 772 | </p></dd><dt><span class="term">
|
|---|
| 773 | G4PSNofStep
|
|---|
| 774 | </span></dt><dd><p>
|
|---|
| 775 | This class scores the number of steps in the cell. A particle
|
|---|
| 776 | weight is not applied.
|
|---|
| 777 | </p></dd><dt><span class="term">
|
|---|
| 778 | G4PSCellCharge
|
|---|
| 779 | </span></dt><dd><p>
|
|---|
| 780 | This class scored the total charge of particles which has stoped
|
|---|
| 781 | in the volume.
|
|---|
| 782 | </p></dd></dl></div><p>
|
|---|
| 783 | </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="sect.Hits.G4VSDFil"></a>4.4.7.
|
|---|
| 784 | <span class="emphasis"><em>G4VSDFilter</em></span> and its derived classes
|
|---|
| 785 | </h3></div></div></div><p>
|
|---|
| 786 | <span class="emphasis"><em>G4VSDFilter</em></span> is an abstract class that represents a track
|
|---|
| 787 | filter to be associated with <span class="emphasis"><em>G4VSensitiveDetector</em></span> or
|
|---|
| 788 | <span class="emphasis"><em>G4VPrimitiveScorer</em></span>. It defines a virtual method
|
|---|
| 789 |
|
|---|
| 790 | </p><div class="informalexample"><pre class="programlisting">
|
|---|
| 791 | <span class="emphasis"><em>G4bool Accept(const G4Step*)</em></span>
|
|---|
| 792 | </pre></div><p>
|
|---|
| 793 |
|
|---|
| 794 | that should return <span class="emphasis"><em>true</em></span> if this particular step should be
|
|---|
| 795 | scored by the <span class="emphasis"><em>G4VSensitiveDetector</em></span> or
|
|---|
| 796 | <span class="emphasis"><em>G4VPrimitiveScorer</em></span>.
|
|---|
| 797 | </p><p>
|
|---|
| 798 | While the user can implement his/her own filter class, Geant4
|
|---|
| 799 | version 8.0 provides the following concrete filter classes:
|
|---|
| 800 |
|
|---|
| 801 | </p><div class="variablelist"><p class="title"><b></b></p><dl><dt><span class="term">
|
|---|
| 802 | G4SDChargedFilter
|
|---|
| 803 | </span></dt><dd><p>
|
|---|
| 804 | All charged particles are accepted.
|
|---|
| 805 | </p></dd><dt><span class="term">
|
|---|
| 806 | G4SDNeutralFilter
|
|---|
| 807 | </span></dt><dd><p>
|
|---|
| 808 | All neutral particles are accepted.
|
|---|
| 809 | </p></dd><dt><span class="term">
|
|---|
| 810 | G4SDParticleFilter
|
|---|
| 811 | </span></dt><dd><p>
|
|---|
| 812 | Particle species which are registered to this filter object by
|
|---|
| 813 | <span class="emphasis"><em>Add("particle_name")</em></span> are accepted. More than one
|
|---|
| 814 | species can be registered.
|
|---|
| 815 | </p></dd><dt><span class="term">
|
|---|
| 816 | G4SDKineticEnergyFilter
|
|---|
| 817 | </span></dt><dd><p>
|
|---|
| 818 | A track with kinetic energy greater than or equal to EKmin and
|
|---|
| 819 | smaller than EKmin is accepted. EKmin and EKmax should be defined
|
|---|
| 820 | as arguments of the constructor. The default values of EKmin and
|
|---|
| 821 | EKmax are zero and DBL_MAX.
|
|---|
| 822 | </p></dd><dt><span class="term">
|
|---|
| 823 | G4SDParticleWithEnergyFilter
|
|---|
| 824 | </span></dt><dd><p>
|
|---|
| 825 | Combination of <span class="emphasis"><em>G4SDParticleFilter</em></span> and
|
|---|
| 826 | <span class="emphasis"><em>G4SDParticleWithEnergyFilter</em></span>.
|
|---|
| 827 | </p></dd></dl></div><p>
|
|---|
| 828 | </p><p>
|
|---|
| 829 | The use of the <span class="emphasis"><em>G4SDParticleFilter</em></span> class is demonstrated
|
|---|
| 830 | in <a href="ch04s04.html#programlist_Hits_2" title="Example 4.15.
|
|---|
| 831 | An example of defining primitive sensitivity classes taken from
|
|---|
| 832 | ExN07DetectorConstruction.
|
|---|
| 833 | ">Example 4.15</a>, where filters which accept gamma,
|
|---|
| 834 | electron, positron and electron/positron are defined.
|
|---|
| 835 | </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="sect.EvtBias.ScorImpRoul.Scor"></a>4.4.8.
|
|---|
| 836 | Scoring for Event Biasing
|
|---|
| 837 | </h3></div></div></div><p>
|
|---|
| 838 | Scoring for Event Biasing (described in <a href="ch03s07.html" title="3.7.
|
|---|
| 839 | Event Biasing Techniques
|
|---|
| 840 | ">Section 3.7</a>) is a
|
|---|
| 841 | very specific use case whereby particle weights and fluxes through importance
|
|---|
| 842 | cells are required. The goals of the scoring technique are to:
|
|---|
| 843 |
|
|---|
| 844 | </p><div class="itemizedlist"><ul type="disc" compact><li><p>
|
|---|
| 845 | appraise particle quantities related to special regions or
|
|---|
| 846 | surfaces,
|
|---|
| 847 | </p></li><li><p>
|
|---|
| 848 | be applicable to all "cells" (physical volumes or replicas) of
|
|---|
| 849 | a given geometry,
|
|---|
| 850 | </p></li><li><p>
|
|---|
| 851 | be customizable.
|
|---|
| 852 | </p></li></ul></div><p>
|
|---|
| 853 | </p><p>
|
|---|
| 854 | Standard scoring must be provided for quantities such as tracks
|
|---|
| 855 | entering a cell, average weight of entering tracks, energy of
|
|---|
| 856 | entering tracks, and collisions inside the cell.
|
|---|
| 857 | </p><p>
|
|---|
| 858 | A number of scorers have been created for this specific appliction:
|
|---|
| 859 | </p><p>
|
|---|
| 860 | </p><div class="variablelist"><p class="title"><b></b></p><dl><dt><span class="term">
|
|---|
| 861 | G4PSNofCollision
|
|---|
| 862 | </span></dt><dd><p>
|
|---|
| 863 | This scorer records the number of collisions that occur within a scored volume/cell.
|
|---|
| 864 | There is the additional possibility to take into account the track weight
|
|---|
| 865 | whilst scoring the number of collisions, via the following command:
|
|---|
| 866 | </p><div class="informalexample"><pre class="programlisting">
|
|---|
| 867 | G4PSNofCollision* scorer1 = new G4PSNofCollision(psName="CollWeight");
|
|---|
| 868 | scorer1->Weighted(true);
|
|---|
| 869 | </pre></div><p>
|
|---|
| 870 | </p></dd><dt><span class="term">
|
|---|
| 871 | G4PSPopulation
|
|---|
| 872 | </span></dt><dd><p>
|
|---|
| 873 | This scores the number of tracks within in a given cell per event.
|
|---|
| 874 | </p></dd><dt><span class="term">
|
|---|
| 875 | G4PSTrackLength
|
|---|
| 876 | </span></dt><dd><p>
|
|---|
| 877 | The track lengths within a cell are measured and if, additionally, the result is desired
|
|---|
| 878 | to be weighted then the following code has to be implemented:
|
|---|
| 879 | </p><div class="informalexample"><pre class="programlisting">
|
|---|
| 880 | G4PSTrackLength* scorer5 = new G4PSTrackLength(psName="SLW");
|
|---|
| 881 | scorer5->Weighted(true);
|
|---|
| 882 | </pre></div><p>
|
|---|
| 883 | Further if the energy track flux is required then the following should be
|
|---|
| 884 | implemented:
|
|---|
| 885 | </p><div class="informalexample"><pre class="programlisting">
|
|---|
| 886 | G4PSTrackLength* scorer6 = new G4PSTrackLength(psName="SLWE");
|
|---|
| 887 | scorer6->Weighted(true);
|
|---|
| 888 | scorer6->MultiplyKineticEnergy(true);
|
|---|
| 889 | MFDet->RegisterPrimitive(scorer6);
|
|---|
| 890 | </pre></div><p>
|
|---|
| 891 |
|
|---|
| 892 | Alternatively to measure the flux per unit velocity then:
|
|---|
| 893 | </p><div class="informalexample"><pre class="programlisting">
|
|---|
| 894 | G4PSTrackLength* scorer7 = new G4PSTrackLength(psName="SLW_V");
|
|---|
| 895 | scorer7->Weighted(true);
|
|---|
| 896 | scorer7->DivideByVelocity(true);
|
|---|
| 897 | MFDet->RegisterPrimitive(scorer7);
|
|---|
| 898 | </pre></div><p>
|
|---|
| 899 |
|
|---|
| 900 | Finally to measure the flux energy per unit velocity then:
|
|---|
| 901 | </p><div class="informalexample"><pre class="programlisting">
|
|---|
| 902 | G4PSTrackLength* scorer8 = new G4PSTrackLength(psName="SLWE_V");
|
|---|
| 903 | scorer8->Weighted(true);
|
|---|
| 904 | scorer8->MultiplyKineticEnergy(true);
|
|---|
| 905 | scorer8->DivideByVelocity(true);
|
|---|
| 906 | MFDet->RegisterPrimitive(scorer8);
|
|---|
| 907 | </pre></div><p>
|
|---|
| 908 | </p></dd></dl></div><p>
|
|---|
| 909 | </p></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ch04s03.html"><img src="AllResources/IconsGIF/prev.gif" alt="Prev"></a> </td><td width="20%" align="center"><a accesskey="u" href="ch04.html"><img src="AllResources/IconsGIF/up.gif" alt="Up"></a></td><td width="40%" align="right"> <a accesskey="n" href="ch04s05.html"><img src="AllResources/IconsGIF/next.gif" alt="Next"></a></td></tr><tr><td width="40%" align="left" valign="top">4.3.
|
|---|
| 910 | Electromagnetic Field
|
|---|
| 911 | </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"> 4.5.
|
|---|
| 912 | Digitization
|
|---|
| 913 | </td></tr></table></div></body></html>
|
|---|
