| Summary: | Energy conservation problem during NeutronInelastic processes for QGSP | ||
|---|---|---|---|
| Product: | Geant4 | Reporter: | Staffan Wranne <wranne> |
| Component: | processes/hadronic/models | Assignee: | dennis.herbert.wright |
| Status: | RESOLVED FIXED | ||
| Severity: | major | ||
| Priority: | P3 | ||
| Version: | 9.4 | ||
| Hardware: | All | ||
| OS: | Linux | ||
Thanks for reporting this. The problem was due to a faulty Lorentz boost and has been fixed. The fix will be included in the beta release of Geant4 9.5 which is due in two weeks. |
Hi. I tried to hit a large block of liquid hydrogen with a 500MeV neutron and occasionally during some n-p inelastic interactions, energy conservation fails and I get out about twice the amount of energy I put in. What I did to produce the problem was: Started out with the original N03 example 1) Changed the physics list to QGSP_BERT 2) Added liquid hydrogen as a material (only 1H, no deuteron and so on) new G4Material("liquidHydrogen", z=1., a= 1.01*g/mole, density= 0.0678*g/cm3); 3) Changed the dimensions of the detector (so that my 500MeV neutron would stop and deposit all its energy) and changed the number of layers to 1. (In vis.mac) /N03/det/setAbsMat liquidHydrogen /N03/det/setGapMat Aerogel /N03/det/setAbsThick 200. m /N03/det/setGapThick 5. cm /N03/det/setNbOfLayers 1 /N03/det/setSizeYZ 150. m /N03/det/update 4) Changed the particle and the energy (In vis.mac) /gun/particle neutron /gun/energy 500 MeV 5) Changed the verbose setting (In vis.mac) /tracking/verbose 2 When I did a run of 1000 events I found that the maximum amount of energy deposited in the Absorber was 1.0044 GeV I have tried to get the seed number for the run and the event (it is event 803 in the run): currentRun.rndm: =============== Uvec 1878463799 0 9876 54321 =============== currentEvent.rndm: =============== Uvec 1878463799 0 590181124 36215192 =============== The output for the beginning of the event: (managed to seed it as the first event): =========================================== Start Run processing. ---> Begin of event: 0 --------- Ranecu engine status --------- Initial seed (index) = 0 Current couple of seeds = 590181124, 36215192 ---------------------------------------- ********************************************************************************************************* * G4Track Information: Particle = neutron, Track ID = 1, Parent ID = 0 ********************************************************************************************************* Step# X Y Z KineE dEStep StepLeng TrakLeng Volume Process 0 -120 m 0 fm 0 fm 500 MeV 0 eV 0 fm 0 fm World initStep 1 -100 m 0 fm 0 fm 500 MeV 0 eV 20 m 20 m World Transportation 2 -98.6 m 0 fm 0 fm 460 MeV 0 eV 1.44 m 21.4 m liquidHydrogen hadElastic :----- List of 2ndaries - #SpawnInStep= 1(Rest= 0,Along= 0,Post= 1), #SpawnTotal= 1 --------------- : -98.6 m 0 fm 0 fm 39.6 MeV proton :----------------------------------------------------------------- EndOf2ndaries Info --------------- 3 -92 m -1.13 m -1.29 m 452 MeV 0 eV 6.82 m 28.3 m liquidHydrogen hadElastic :----- List of 2ndaries - #SpawnInStep= 1(Rest= 0,Along= 0,Post= 1), #SpawnTotal= 2 --------------- : -92 m -1.13 m -1.29 m 8.78 MeV proton :----------------------------------------------------------------- EndOf2ndaries Info --------------- 4 -77.7 m -4.69 m -2.61 m 445 MeV 0 eV 14.8 m 43.1 m liquidHydrogen hadElastic :----- List of 2ndaries - #SpawnInStep= 1(Rest= 0,Along= 0,Post= 1), #SpawnTotal= 3 --------------- : -77.7 m -4.69 m -2.61 m 6.82 MeV proton :----------------------------------------------------------------- EndOf2ndaries Info --------------- 5 -73.3 m -5.46 m -2.61 m 429 MeV 0 eV 4.41 m 47.5 m liquidHydrogen hadElastic :----- List of 2ndaries - #SpawnInStep= 1(Rest= 0,Along= 0,Post= 1), #SpawnTotal= 4 --------------- : -73.3 m -5.46 m -2.61 m 15.5 MeV proton :----------------------------------------------------------------- EndOf2ndaries Info --------------- 6 -71.8 m -5.95 m -2.43 m 0 eV 0 eV 1.65 m 49.1 m liquidHydrogen NeutronInelastic :----- List of 2ndaries - #SpawnInStep= 5(Rest= 0,Along= 0,Post= 5), #SpawnTotal= 9 --------------- : -71.8 m -5.95 m -2.43 m 132 MeV pi0 : -71.8 m -5.95 m -2.43 m 132 MeV neutron : -71.8 m -5.95 m -2.43 m 101 MeV proton : -71.8 m -5.95 m -2.43 m 421 MeV proton : -71.8 m -5.95 m -2.43 m 8.42 MeV neutron :----------------------------------------------------------------- EndOf2ndaries Info --------------- ============================================================== During the NeutronInelastic interaction a lot of energy is produced. I hope that the information helps to identify the issues. I'll gladly provide more if needed. Best regards, Staffan