------------------------------Advanced Example--------------------------------- README FILE NB: The documentation for this example is in the process of being updated. Please go to http://www.ge.infn.it/geant4/examples/ for the most up-to-date description, manual, design documentation and users requirement/traceability. JUNE 2002: The underground physics example has been updated since the December Geant4.0 release to include: 1) Analysis, using AIDA 2.2 and tested against Anaphe 4.0 2) Full lab geometry - important for neutron scattering 3) Updated macros/messengers 4) Correction of a few minor features The messengers can be seen from typing help within the UI. Additional file handling and time/energy cut messengers have been implemented. (1) and (2) are discussed more fully below Note: Due to the importation of data files during the initialisation stage of Geant4, load-time may be in excess of 5 minutes. UNDERGROUND PHYSICS An example of a underground dark matter experiment. Please see the UserRequirements.txt and related web-pages referred to at the end of that document. Over-view: A single liquid xenon cell is simulated within Geant4 and the scintillation light produced from interactions from various calibration species is recorded as PhotoMultiplier hits. The output is then written to an ASCII file for future off-line analysis. Geometry: Experimental set-up: G4double worldWidth = 470.0*cm + 2.*wallThick; // "x" G4double worldLength = 690.0*cm + 2.*wallThick; // "y" G4double worldHeight = 280.0*cm + 2.*wallThick; // "z" A "cavern" of dimensions 5.18m x 7.38m x 3.28m with concrete walls is defined as the World Volume. A laboratory geometry is incorporated included desks, cupboards, door and windows. For ease this is included in a separate ".icc" file which can be removed should the code seem cumbersome. In the centre of the cavern a steel vacuum vessel containing liquid and gaseous xenon is placed. The internal construction of the vessel accurately reproduces an existing prototype Dark Matter detector which allows experimental comparison. The active detector volume is defined by a series of metal rings, complemented by a cover mirror and a PMT immersed in the liquid. Two grids and a thermalising copper shield are also incorporated. The liquid/gas interface is located 6mm away from the mirror surface. A Am241 calibration source is suspended from one of the grids in the liquid phase, above the PMT. XXX================XXX mirror XXX________________XXX gas phase XXX XXX XXX XXX liquid phase XXX XXX XXX.......U........XXX grid + calibrator XXX................XXX grid XXX| |XXX | ___------___ | || PMT || || || Hits Output (file "hits.out"): An ASCII file containing the following information: Evt # : event number Etot, MeV : energy deposited in liquid xenon LXe hits : number of hits in liquid xenon LXeTime, ns : time of first hit in liquid xenon PMT hits : number of hits in PMT (photocathode) PmtTime, ns : average PMT hit time relative to LXeTime First hit : first particle to hit liquid xenon Flags : particles contributing to energy deposition Seeds : the initial seed values for given hit events Note: The time information PmtTime is erroneous when forcing nuclear decay with the RadioactiveDecay module due to the precision required to detect nanosecond scintillation times on a global time of 432 years (in the case of 241Am decay). Pmt Output (file "pmt.out"): Photon hit positions within the PMT face (overwritten every event): "Hit# X, mm Y, mm Z, mm" To Run: Either run the macro files interactively or in batch with the command DMX macro_name.mac. Macros: initInter.mac Initialisation macro for interactive mode. gamma.mac Shoots one 60 keV gamma upwards from the calibrator and traces the scintillation light produced in LXe to the PMT. All tracks are drawn with custom colours. PMT hits in photocathode are also shown. Event summary is writen to file "hits.out". gamma_1000.mac Similar to above, but 1000 gammas are emmited isotropically from the source. No hits or tracks are draw, and the verbosity is reduced. alpha.mac Shoots one 5.486 MeV alpha particle upwards from the calibrator and traces the scintillation light to the PMT. All tracks except optical photons are drawn. Event summary is written to file "hits.out" and PMT hits to file "pmt.out". alpha_1000.mac Similar to above, but 1000 alphas are emmited isotropically from the source. No tracks are stored, and the verbosity is reduced. Event summary is written to file "hits.out", PMT hits are not written out. neutron.mac Shoots one 2.48 MeV neutron inside the room aimed at the detector. All tracks except scintillation photons are drawn (custom colours). Gammas are not killed at the concrete wall. Event summery is written to file "hits.out". ambe_spectrum.mac Produces a spectrum of neutrons according to an approximation of a Am/Be neutron source. However, this uses the GPS and therefore will only work after compilation with the DMXENV_GPS_USE environment variable (see below) sourceAm241.mac Forces the decay of 241Am nuclei in the calibrator and tracks the resulting particles (237Np + alpha + gamma from 237Np de-excitation). All tracks are drawn except scintillation photons. Event summery is written to file "hits.out". -> To be added for a future release sourceAm241_1000.mac Similar to above but for 1000 events. No tracks are stored. -> To be added for a future release Note: The following environment variables need to be set: G4RADIOACTIVEDATA : points to Radioactive Decay Data files G4LEDATA : points to low energy data base G4LEVELGAMMADATA : points to PhotoEvaporation data NeutronHPCrossSections : points to neutron data files In addition if you require to use the full General Particle Source then the variable DMXENV_GPS_USE can be set. The DMX gun is still included in order to allow forward compatibility should the GPS change. ANALYSIS: In order to use the AIDA 3.2.1 compliant analysis set the environment variable G4ANALYSIS_USE before building. If a previous build exists a gmake clean has to be executed. setenv G4ANALYSIS_USE 1 then gmake The program should then produce hbook histogram files Using AIDA 3.2.1 interfaces three different analysis packages can be utilised: Java Analysis Studio (JAS) OpenScientist PI Please for more information look at http://aida.freehep.org SEEDS: The seeds of event hits are stored in the hit record file. These can be used to repeat events for visualisation, test crashes/idiosyncracies: /random/setDirectoryName ./seeds /random/resetEngineFrom currentEvent.rndm /random/saveThisEvent /random/setSavingFlag The file currentEvent.rndm should contain the two seeds which were outputed in the scintHit file. ERRORS: When running interactively the following error will be shown: BooleanProcessor::caseIE : unimplemented case BooleanProcessor::caseIE : unimplemented case BooleanProcessor::caseIE : unimplemented case BooleanProcessor::caseIE : unimplemented case BooleanProcessor::caseIE : unimplemented case BooleanProcessor::caseIE : unimplemented case BooleanProcessor: boolean operation failed BooleanProcessor::caseIE : unimplemented case BooleanProcessor::caseIE : unimplemented case BooleanProcessor::caseIE : unimplemented case BooleanProcessor::caseIE : unimplemented case BooleanProcessor: boolean operation failed This is a "feature" of the visualisation of boolean volumes, but does not affect functionality/performance so can be ignored. NB: If using explicit libraries (?) i.e. non-shared then compilation time with neutrons in physics list is very long (>5 minutes) - check this............. It is more efficient to use shared libraries that are loaded at run-time with increased initialisation time (at run-time). Also if using shared libraries the load time at run-time may be several minutes - this is partially due to the neutron implementation requires full data sets for each isotope being specified. -------------------------------------- If running on Redhat 7.0 or above set G4SYSTEM to Linux-g++, alternatively you can install backward compatibility to egcs, however, requires config/sys/Linux-egcs.gmk to be altered so that CXX is set to kgcc (compared to g++ in original file) -------------------------------------- Alex Howard, 29/11/01 updated 18/06/02