Gabriele Cosmo
288 lines
10 KiB
Plaintext
288 lines
10 KiB
Plaintext
------------------------------Advanced Example--------------------------------- README FILE
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NB: The documentation for this example is in the process of being updated.
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Please go to http://www.ge.infn.it/geant4/examples/ for the most up-to-date
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description, manual, design documentation and users requirement/traceability.
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JUNE 2002:
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The underground physics example has been updated since the December Geant4.0
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release to include: 1) Analysis, using AIDA 2.2 and tested against Anaphe 4.0
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2) Full lab geometry - important for neutron scattering
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3) Updated macros/messengers
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4) Correction of a few minor features
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The messengers can be seen from typing help within the UI.
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Additional file handling and time/energy cut messengers have been implemented.
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(1) and (2) are discussed more fully below
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Note: Due to the importation of data files during the initialisation stage of
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Geant4, load-time may be in excess of 5 minutes.
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UNDERGROUND PHYSICS
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An example of a underground dark matter experiment.
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Please see the UserRequirements.txt and related web-pages referred to
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at the end of that document.
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Over-view:
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A single liquid xenon cell is simulated within Geant4 and the scintillation
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light produced from interactions from various calibration species is recorded
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as PhotoMultiplier hits. The output is then written to an ASCII file for
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future off-line analysis.
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Geometry:
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Experimental set-up:
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G4double worldWidth = 470.0*cm + 2.*wallThick; // "x"
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G4double worldLength = 690.0*cm + 2.*wallThick; // "y"
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G4double worldHeight = 280.0*cm + 2.*wallThick; // "z"
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A "cavern" of dimensions 5.18m x 7.38m x 3.28m with concrete walls is defined
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as the World Volume. A laboratory geometry is incorporated included desks,
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cupboards, door and windows. For ease this is included in a separate ".icc"
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file which can be removed should the code seem cumbersome. In the centre of
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the cavern a steel vacuum vessel containing liquid and gaseous xenon is placed.
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The internal construction of the vessel accurately reproduces an existing
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prototype Dark Matter detector which allows experimental comparison. The active
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detector volume is defined by a series of metal rings, complemented by
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a cover mirror and a PMT immersed in the liquid. Two grids and a
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thermalising copper shield are also incorporated. The liquid/gas
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interface is located 6mm away from the mirror surface. A Am241
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calibration source is suspended from one of the grids in the liquid
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phase, above the PMT.
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XXX================XXX mirror
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XXX________________XXX gas phase
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XXX XXX
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XXX XXX liquid phase
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XXX XXX
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XXX.......U........XXX grid + calibrator
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XXX................XXX grid
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XXX| |XXX
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| ___------___ |
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|| PMT ||
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|| ||
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Hits Output (file "hits.out"):
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An ASCII file containing the following information:
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Evt # : event number
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Etot, MeV : energy deposited in liquid xenon
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LXe hits : number of hits in liquid xenon
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LXeTime, ns : time of first hit in liquid xenon
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PMT hits : number of hits in PMT (photocathode)
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PmtTime, ns : average PMT hit time relative to LXeTime
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First hit : first particle to hit liquid xenon
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Flags : particles contributing to energy deposition
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Seeds : the initial seed values for given hit events
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Note:
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The time information PmtTime is erroneous when forcing nuclear
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decay with the RadioactiveDecay module due to the precision
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required to detect nanosecond scintillation times on a global
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time of 432 years (in the case of 241Am decay).
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Pmt Output (file "pmt.out"):
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Photon hit positions within the PMT face (overwritten every event):
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"Hit# X, mm Y, mm Z, mm"
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To Run:
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Either run the macro files interactively or in batch with the command
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DMX macro_name.mac.
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Macros:
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initInter.mac
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Initialisation macro for interactive mode.
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gamma.mac
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Shoots one 60 keV gamma upwards from the calibrator and traces the
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scintillation light produced in LXe to the PMT. All tracks are drawn
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with custom colours. PMT hits in photocathode are also shown. Event
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summary is writen to file "hits.out".
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gamma_1000.mac
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Similar to above, but 1000 gammas are emmited isotropically from the
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source. No hits or tracks are draw, and the verbosity is reduced.
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alpha.mac
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Shoots one 5.486 MeV alpha particle upwards from the calibrator and
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traces the scintillation light to the PMT. All tracks except
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optical photons are drawn. Event summary is written to file
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"hits.out" and PMT hits to file "pmt.out".
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alpha_1000.mac
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Similar to above, but 1000 alphas are emmited isotropically from the
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source. No tracks are stored, and the verbosity is reduced. Event
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summary is written to file "hits.out", PMT hits are not written out.
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neutron.mac
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Shoots one 2.48 MeV neutron inside the room aimed at the detector.
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All tracks except scintillation photons are drawn (custom colours).
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Gammas are not killed at the concrete wall. Event summery is written
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to file "hits.out".
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ambe_spectrum.mac
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Produces a spectrum of neutrons according to an approximation of a Am/Be
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neutron source. However, this uses the GPS and therefore will only work
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after compilation with the DMXENV_GPS_USE environment variable (see below)
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sourceAm241.mac
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Forces the decay of 241Am nuclei in the calibrator and tracks the
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resulting particles (237Np + alpha + gamma from 237Np
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de-excitation). All tracks are drawn except scintillation photons.
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Event summery is written to file "hits.out".
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-> To be added for a future release
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sourceAm241_1000.mac
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Similar to above but for 1000 events. No tracks are stored.
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-> To be added for a future release
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Note:
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The following environment variables need to be set:
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G4RADIOACTIVEDATA : points to Radioactive Decay Data files
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G4LEDATA : points to low energy data base - G4EMLOW0.5
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G4LEVELGAMMADATA : points to PhotoEvaporation data
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NeutronHPCrossSections : points to neutron data files G4NDL3.5
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In addition if you require to use the full General Particle Source then the
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variable DMXENV_GPS_USE can be set. The DMX gun is still included in order to
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allow forward compatibility should the GPS change.
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ANALYSIS:
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In order to use the AIDA 2.2 compliant analysis set the environment variable
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G4ANALYSIS_USE before building. If a previous build exists a gmake clean has
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to be executed.
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export G4ANALYSIS_USE=1
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To link with anaphe, first execute the anaphe installation script:
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source anaphe
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then gmake
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The program should then produce hbook histogram files as well as interactively
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two summary pages from QPLOTTER - outputing with postscript summary1.ps and
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summary2.ps
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In addition a lizard python script is included for reference:
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start lizard:
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lizard
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exe("DMX.py")
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Subsequent runs will require source of anaphe_start.sh
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source anaphe_start.sh
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before executing DMX
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NB: When running the program the output histogram file has to be "new"
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therefore if it has the same name as an existing file the program will crash.
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See http://cern.ch/anaphe for more information about ANAPHE/Lizard
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AIDA 2.2 information is available at http://www.aida.org
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Using AIDA 2.2 interfaces three different analysis packages can be utilised:
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Java Analysis Studio (JAS)
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OpenScientist
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Anaphe/Lizard
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At cern instead of executing the anaphe script see below:
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[
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AT CERN the following has to be executed in order to pick-up anaphe:
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execute the following lines _before_ gmake,
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select the Anaphe version you want to use (4.0.1-sec for RH61 "old" compiler,
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4.0.1 for RH61, new compiler (gcc-2.95.2)):
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export PATH=$PATH:/afs/cern.ch/sw/lhcxx/specific/redhat61/egcs_1.1.2/4.0.1-sec/bin
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source /afs/cern.ch/sw/lhcxx/share/LHCXX/4.0.1-sec/install/sharedstart.sh
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(for the new compiler, use (sh derivates):
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export PATH=$PATH:/afs/cern.ch/sw/lhcxx/specific/redhat61/gcc-2.95.2/4.0.1/bin
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source /afs/cern.ch/sw/lhcxx/share/LHCXX/4.0.1/install/sharedstart.sh)
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or, for [t]csh fans (still "old" compiler):
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setenv PATH ${PATH}:/afs/cern.ch/sw/lhcxx/specific/redhat61/egcs_1.1.2/4.0.1-sec/bin
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source /afs/cern.ch/sw/lhcxx/share/LHCXX/4.0.1-sec/install/sharedstart.csh
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]
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SEEDS:
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The seeds of event hits are stored in the hit record file. These can be used
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to repeat events for visualisation, test crashes/idiosyncracies:
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/random/setDirectoryName ./seeds
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/random/resetEngineFrom currentEvent.rndm
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/random/saveThisEvent
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/random/setSavingFlag
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The file currentEvent.rndm should contain the two seeds which were outputed in
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the scintHit file.
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ERRORS:
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When running interactively the following error will be shown:
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BooleanProcessor::caseIE : unimplemented case
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BooleanProcessor::caseIE : unimplemented case
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BooleanProcessor::caseIE : unimplemented case
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BooleanProcessor::caseIE : unimplemented case
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BooleanProcessor::caseIE : unimplemented case
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BooleanProcessor::caseIE : unimplemented case
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BooleanProcessor: boolean operation failed
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BooleanProcessor::caseIE : unimplemented case
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BooleanProcessor::caseIE : unimplemented case
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BooleanProcessor::caseIE : unimplemented case
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BooleanProcessor::caseIE : unimplemented case
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BooleanProcessor: boolean operation failed
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This is a "feature" of the visualisation of boolean volumes, but does not
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affect functionality/performance so can be ignored.
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NB:
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If using explicit libraries (?) i.e. non-shared then compilation time with
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neutrons in physics list is very long (>5 minutes) - check this.............
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It is more efficient to use shared libraries that are loaded at run-time with
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increased initialisation time (at run-time).
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Also if using shared libraries the load time at run-time may be several minutes
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- this is partially due to the neutron implementation requires full data sets
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for each isotope being specified.
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--------------------------------------
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If running on Redhat 7.0 or above set G4SYSTEM to Linux-g++, alternatively you
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can install backward compatibility to egcs, however, requires
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config/sys/Linux-egcs.gmk to be altered so that CXX is set to kgcc
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(compared to g++ in original file)
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--------------------------------------
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Alex Howard, 29/11/01
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updated 18/06/02
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