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0001 ------------------------------Advanced Example--------------------------------- README FILE
0002
0003 Note: Due to the importation of data files during the initialisation stage of
0004 Geant4, load-time may be in excess of 5 minutes.
0005
0006 UNDERGROUND PHYSICS
0007
0008 An example of a underground dark matter experiment.
0009
0010 Please see the UserRequirements.txt and related web-pages referred to
0011 at the end of that document.
0012
0013 Over-view:
0014 A single liquid xenon cell is simulated within Geant4 and the scintillation
0015 light produced from interactions from various calibration species is recorded
0016 as PhotoMultiplier hits. The output is then written to an ASCII file for
0017 future off-line analysis.
0018
0019 Geometry:
0020 Experimental set-up:
0021
0022 G4double worldWidth = 470.0*cm + 2.*wallThick; // "x"
0023 G4double worldLength = 690.0*cm + 2.*wallThick; // "y"
0024 G4double worldHeight = 280.0*cm + 2.*wallThick; // "z"
0025
0026
0027
0028 A "cavern" of dimensions 5.18m x 7.38m x 3.28m with concrete walls is defined
0029 as the World Volume. A laboratory geometry is incorporated included desks,
0030 cupboards, door and windows. For ease this is included in a separate ".icc"
0031 file which can be removed should the code seem cumbersome. In the centre of
0032 the cavern a steel vacuum vessel containing liquid and gaseous xenon is placed.
0033 The internal construction of the vessel accurately reproduces an existing
0034 prototype Dark Matter detector which allows experimental comparison. The active
0035 detector volume is defined by a series of metal rings, complemented by
0036 a cover mirror and a PMT immersed in the liquid. Two grids and a
0037 thermalising copper shield are also incorporated. The liquid/gas
0038 interface is located 6mm away from the mirror surface. A Am241
0039 calibration source is suspended from one of the grids in the liquid
0040 phase, above the PMT.
0041
0042 XXX================XXX mirror
0043 XXX________________XXX gas phase
0044 XXX XXX
0045 XXX XXX liquid phase
0046 XXX XXX
0047 XXX.......U........XXX grid + calibrator
0048 XXX................XXX grid
0049 XXX| |XXX
0050 | ___------___ |
0051 || PMT ||
0052 || ||
0053
0054
0055 Hits Output (file "hits.out"):
0056 An ASCII file containing the following information:
0057 Evt # : event number
0058 Etot, MeV : energy deposited in liquid xenon
0059 LXe hits : number of hits in liquid xenon
0060 LXeTime, ns : time of first hit in liquid xenon
0061 PMT hits : number of hits in PMT (photocathode)
0062 PmtTime, ns : average PMT hit time relative to LXeTime
0063 First hit : first particle to hit liquid xenon
0064 Flags : particles contributing to energy deposition
0065 Seeds : the initial seed values for given hit events
0066
0067 Note:
0068
0069 The time information PmtTime is erroneous when forcing nuclear
0070 decay with the RadioactiveDecay module due to the precision
0071 required to detect nanosecond scintillation times on a global
0072 time of 432 years (in the case of 241Am decay).
0073
0074
0075 Pmt Output (file "pmt.out"):
0076 Photon hit positions within the PMT face (overwritten every event):
0077 "Hit# X, mm Y, mm Z, mm"
0078
0079
0080 To Run:
0081 Either run the macro files interactively or in batch with the command
0082 DMX macro_name.mac.
0083
0084
0085 Macros:
0086
0087 initInter.mac
0088 Initialisation macro for interactive mode.
0089
0090 gamma.mac
0091 Shoots one 60 keV gamma upwards from the calibrator and traces the
0092 scintillation light produced in LXe to the PMT. All tracks are drawn
0093 with custom colours. PMT hits in photocathode are also shown. Event
0094 summary is writen to file "hits.out".
0095
0096 gamma_1000.mac
0097 Similar to above, but 1000 gammas are emmited isotropically from the
0098 source. No hits or tracks are draw, and the verbosity is reduced.
0099
0100 alpha.mac
0101 Shoots one 5.486 MeV alpha particle upwards from the calibrator and
0102 traces the scintillation light to the PMT. All tracks except
0103 optical photons are drawn. Event summary is written to file
0104 "hits.out" and PMT hits to file "pmt.out".
0105
0106 alpha_1000.mac
0107 Similar to above, but 1000 alphas are emmited isotropically from the
0108 source. No tracks are stored, and the verbosity is reduced. Event
0109 summary is written to file "hits.out", PMT hits are not written out.
0110
0111 neutron.mac
0112 Shoots one 2.48 MeV neutron inside the room aimed at the detector.
0113 All tracks except scintillation photons are drawn (custom colours).
0114 Gammas are not killed at the concrete wall. Event summery is written
0115 to file "hits.out".
0116
0117 ambe_spectrum.mac
0118 Produces a spectrum of neutrons according to an approximation of a Am/Be
0119 neutron source. However, this uses the GPS and therefore will only work
0120 after compilation with the DMXENV_GPS_USE environment variable (see below)
0121
0122
0123 sourceAm241.mac
0124 Forces the decay of 241Am nuclei in the calibrator and tracks the
0125 resulting particles (237Np + alpha + gamma from 237Np
0126 de-excitation). All tracks are drawn except scintillation photons.
0127 Event summery is written to file "hits.out".
0128 -> To be added for a future release
0129
0130
0131 sourceAm241_1000.mac
0132 Similar to above but for 1000 events. No tracks are stored.
0133 -> To be added for a future release
0134
0135
0136 Note:
0137 The following environment variables need to be set:
0138 G4RADIOACTIVEDATA : points to Radioactive Decay Data files
0139 G4LEDATA : points to low energy data base
0140 G4LEVELGAMMADATA : points to PhotoEvaporation data
0141 NeutronHPCrossSections : points to neutron data files
0142
0143 In addition if you require to use the full General Particle Source then the
0144 variable DMXENV_GPS_USE can be set. The DMX gun is still included in order to
0145 allow forward compatibility should the GPS change.
0146
0147
0148 ANALYSIS:
0149
0150 The program should produce ROOT-based histogram files. It is possible to
0151 produce the output in XML-compliant format by changing the G4AnalysisManager default file type in DMXRunAction::Book().
0152
0153 SEEDS:
0154
0155 The seeds of event hits are stored in the hit record file. These can be used
0156 to repeat events for visualisation, test crashes/idiosyncracies:
0157
0158 /random/setDirectoryName ./seeds
0159 /random/resetEngineFrom currentEvent.rndm
0160 /random/saveThisEvent
0161 /random/setSavingFlag
0162
0163 The file currentEvent.rndm should contain the two seeds which were outputed in
0164 the scintHit file.
0165
0166 ERRORS:
0167
0168 When running interactively the following error will be shown:
0169
0170 BooleanProcessor::caseIE : unimplemented case
0171 BooleanProcessor::caseIE : unimplemented case
0172 BooleanProcessor::caseIE : unimplemented case
0173 BooleanProcessor::caseIE : unimplemented case
0174 BooleanProcessor::caseIE : unimplemented case
0175 BooleanProcessor::caseIE : unimplemented case
0176 BooleanProcessor: boolean operation failed
0177 BooleanProcessor::caseIE : unimplemented case
0178 BooleanProcessor::caseIE : unimplemented case
0179 BooleanProcessor::caseIE : unimplemented case
0180 BooleanProcessor::caseIE : unimplemented case
0181 BooleanProcessor: boolean operation failed
0182
0183 This is a "feature" of the visualisation of boolean volumes, but does not
0184 affect functionality/performance so can be ignored.
0185
0186 NB:
0187 If using explicit libraries (?) i.e. non-shared then compilation time with
0188 neutrons in physics list is very long (>5 minutes) - check this.............
0189 It is more efficient to use shared libraries that are loaded at run-time with
0190 increased initialisation time (at run-time).
0191
0192 Also if using shared libraries the load time at run-time may be several minutes
0193 - this is partially due to the neutron implementation requires full data sets
0194 for each isotope being specified.
0195
0196
0197 --------------------------------------
0198
0199 If running on Redhat 7.0 or above set G4SYSTEM to Linux-g++, alternatively you
0200 can install backward compatibility to egcs, however, requires
0201 config/sys/Linux-egcs.gmk to be altered so that CXX is set to kgcc
0202 (compared to g++ in original file)
0203
0204 --------------------------------------
0205
0206
0207 Alex Howard, 29/11/01
0208 updated 18/06/02
0209
