| Geant4 Cross Reference |
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2 Channeling effect in Gean
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4 Enrico Bagli - INFN and University
5 bagli@fe.infn.it
6
7 This example shows how channeling in bent crys
8 in Geant4
9
10 1.INTRODUCTION
11 The example simulates the channeling of 400 Ge
12 Si crystal. Channeling occurs when particles e
13 with atomic planes or axes. In bent crystals,
14 trapped between atomic planes and follow the c
15 being deflected. If the particle direction is
16 crystal plane is reflected to the opposite dir
17 to channeling, i.e., it suffer ‘volume refle
18 provides the physical model for planar channel
19 reflection in bent crystals.
20
21 2.GEOMETRY
22 The geometry is a bent Si crystal with three S
23 -9.998 m, -0.320 m and 10.756 m with respect t
24 the bent crystal itself. The Si detectors allo
25 incoming and outgoing angle after the interact
26 The geometry is all under vacuum.
27
28 3.PRIMARY EVENT
29 The primary events are 400 GeV/c protons launc
30 crystal with 13.36 microrad x 11.25 microrad d
31
32 4.PHYSICS
33 In the example the physics of channeling and v
34 has been added to the standard Geant4 physics.
35 of the used model can be found in the paper â€
36 interaction of high-energy particles in straig
37 crystals implemented in Geant4’ by E. Bagli
38 online at http://arxiv.org/abs/1403.5819
39
40 5.EXECUTION & OUTPUT
41 The executable must be run from within the sou
42 to ensure that it can find the path for crysta
43
44 Data files for Si crystal interplanar potentia
45 are stored in a subdirectory named ’data’
46
47 Upon execution, the 2009_PLB680_129.mac macro
48 example with 1000 protons.
49
50 Use
51 /xtal/setBR XXX 0. 0. m
52 To change crystal bending to XXX meters
53
54 Use
55 /xtal/setSize 1.0 70. XXX mm
56 To change crystal length to XXX millimeter
57
58 Use
59 /xtal/potfilename data/Si220pl
60 To select the (110) Si crystal plane of channe
61
62 GPS commands are used for the primary generato
63
64 The output is the ExExhCh.root file with the T
65 has the leaves:
66 - angXin : incoming particle X angle at the cr
67 - angYin : incoming particle Y angle at the cr
68 - posXin : hitting X position of the particle
69 - posYin : hitting Y position of the particle
70 - angXout: outgoing particle X angle out of th
71 - angYout: outgoing particle Y angle out of th