4 ===========================================================
5 General Information about MUON Geometry
6 ===========================================================
8 Our geometry is described in the geometry builder classes.
9 Main geometrical constants are set in the class AliMUONConstants.
10 The code can then generate the geometry data files
11 transform.dat and svmap.dat (see description below) via the macro
12 MUONGenerateGeometryData.C (more info below).
13 The geometry data files have to be recreated each time the code
14 of the geometry is modified. The info (well updated) in this files
15 (svmap) is need during the simulation.
16 We can also decide to use the transform.dat file as input of our
17 geometry. This allows for changing the position of our detection elements
18 and/or half-planes (half-chambers in code jargon) without modifying
19 and recompiling the code.
21 First step in the official aliroot simulation process is to create
22 the geometry.root file from the builders to build the MUON geometry
23 within the geometrical modeler framework of root.
24 Then aliroot takes the geometry.root file as a unique geometrical
25 info of our apparatus during the generation and the reconstruction
26 and analysis (if needed)
28 Misalignments are in the official AliRoot code applied to the geometry.root
32 Geometry data files description
37 List of transformations for chambers geometry modules and detection
40 KEY ID [nofDE] pos: posX posY posZ rot: theX phiX theY phiY theZ phiZ
43 ID = chamberId or detElemId
44 pos: posX posY posZ = position in cm
45 rot: theX phiX theY phiY theZ phiZ = rotation angles as in Geant3 in deg
50 Map of sensitive volumes to detction element Ids;
55 volpath = volume path in format /volname1_copyNo1/volname2_copyNo2/...
56 detElemId = detection element Id
60 ============================================================
61 How to check the Geometry with the new Geometrical modeler
62 ftp://root.cern.ch/root/doc/chapter16.pdf
63 http://agenda.cern.ch/fullAgenda.php?ida=a05212
64 ============================================================
65 gAlice->Init("$ALICE_ROOT/MUON/Config.C");
66 gGeoManager->GetMasterVolume()->Draw();
69 ============================================================
70 How to check the overlap with the new Geometrical modeler
71 ftp://root.cern.ch/root/doc/chapter16.pdf
72 http://agenda.cern.ch/fullAgenda.php?ida=a05212
73 ============================================================
74 gAlice->Init("$ALICE_ROOT/MUON/Config.C");
75 gGeoManager->CheckOverlaps();
76 gGeoManager->PrintOverlaps();
80 ===========================================================
81 Macro MUONGenerateGeometryData.C
82 ===========================================================
84 Macro for generating the geometry data files
87 - MUON/data/transform.dat file contains the transformations
88 data (translation and rotation) for all alignable objects
89 (modules & detection elements)
90 - MUON/data/svmap.dat file contains all the information to link
91 each geant volume (it can be extended to other virtual MC) with
92 a detection element. The point here is that a given detection
93 element, i.e. a slat chamber can consist of more geant volumes.
94 the correspondence is then defined in an input file.
95 Each time there is a change in the definition of MC geometry, these
96 input files must be re-generated via the macro
97 MUONGenerateGeometryData.C
99 To be run from aliroot:
100 .x MUONGenerateGeometryData.C
102 The generated files do not replace the existing ones
103 but have different names (with extension ".out").
104 Replacement with new files has to be done manually.
107 ===========================================================
108 Macros to generate Mis-alignment data
109 ===========================================================
111 Macro for generating the geometry mis-alignment data:
112 MakeMUONFullMisAlignment.C
113 MakeMUONResMisAlignment.C
114 MakeMUONZeroMisAlignment.C
116 To be run from aliroot:
117 .x MakeMUONFullMisAlignment.C etc.
119 If the environment variable TOCDB is not set to "kTRUE",
120 the misalignment data are generated in a local file:
121 (MUONFullMisalignment.root, etc.)
123 If the data are stored in CDB, the storage can be specified in
124 the environment variable STORAGE. The misalignment data are then
125 generated in the CDB folder (defaults are ResMisAlignCDB and FullMisAlignCDB
126 in the working directory). Inside the local CDB the path for the
127 alignment data is (and must be) "MUON/Align/Data/".
128 Residual misalignment: Default is our current estimate of
129 misalignment after all our alignment procedure has been applied.
130 Full misalignment: Default is our current estimate of initial
133 ==========================================================
134 How to check the alignment software
135 ==========================================================
137 The script AlirootRun_MUONtestAlign.sh allows you to check the software for
138 the alignment with physics tracks. The script will:
139 - Generate a misaligned geometry in a local CDB (default FullMisAlignCDB)
140 - Simulate 1000 events using previously misaligned geometry
141 - Reconstruct the events using perfect geometry
142 - Run the alignment code over the above events using MUONAlignment.C
144 To run you need to type:
145 $ALICE_ROOT/MUON/AlirootRun_MUONtestAlign.sh
147 The results of the test are saved in test_align/ directory. The file measShifts.root
148 contains useful graphs for studying the alignment performances. A local CDB
149 containing the realigned geometry is also created (default is ReAlignCDB). The
150 file $ALICE_ROOT/MUON/data/transform2ReAlign.dat contains the
151 transformations describing the realigned geometry to be compared with the
152 used misaligned geometry $ALICE_ROOT/MUON/data/transform2.dat.
154 IMPORTANT NOTE: For a useful test of the alignment performances, the
155 order of 100 000 tracks is needed, it is then advisable to generate and
156 reconstruct enough events separately and run MUONAlignment.C providing a file list