<html><body><div style="font-family: arial, helvetica, sans-serif; font-size: 12pt; color: #000000"><div>Dear Gate users,</div><div><br></div><div>I'm working with a very simple model : 1 sphere of G4-WATER (my cell) with at its center a repeater of smaller spheres (my nanoparticles) each composed as follows:</div><div><br></div><blockquote><div>AGuIX_bis: d=1.58 g/cm3 ; n=6 ; state=Solid<br> +el: name=Bismuth ; f=0.16<br> +el: name=Silicon ; f=0.10<br> +el: name=Carbon ; f=0.25<br> +el: name=Nitrogen ; f=0.08<br> +el: name=Oxygen ; f=0.21<br> +el: name=Hydrogen ; f=0.20</div></blockquote><div><br></div><div>I'm looking at the deposited dose on the nanoparticles focci and on water areas through a doseActor while changing the number of nanoparticles.</div><div>Running multiple times my simulation with 15625 nanoparticles, I obtain mean values on the nanoparticles focci in Gy like</div><ul><li>0</li><li>6.246</li><li>0.049</li><li>0</li><li>0.898</li><li>0</li><li>2.548</li></ul><div>I don't understand the zero values... ?</div><div><br data-mce-bogus="1"></div><div>I have a gamma beam and I send 300 000 Bq for a 60 secondes irradiation simulation.<br data-mce-bogus="1"></div><div>My source is an histogram that looks like that<br data-mce-bogus="1"></div><div><img src="cid:b64043bc1299643e415428735f7545abefd0a36f@zimbra" data-mce-src="cid:b64043bc1299643e415428735f7545abefd0a36f@zimbra"></div><div>I'm not a physicist but with 300 000 (Bq) / 40 (my surface) = 7500 photons per um^2 , isn't it strange to obtain no gray at all ?<br></div><div><br data-mce-bogus="1"></div><div>Here is my code:</div><div><br></div><div>MAIN.MAC</div><div><br></div><blockquote><div>/gate/geometry/setMaterialDatabase ../data/GateMaterials.db</div><div><br>/control/execute world.mac<br>/control/execute physics.mac<br>/control/execute detectors.mac<br><br>/gate/run/initialize<br><br>/control/execute 5sourceSpectrumMeV.mac<br><br>/gate/application/setTimeSlice 60. s<br>/gate/application/setTimeStart 0. s<br>/gate/application/setTimeStop 60. s<br><br>/gate/random/setEngineName MersenneTwister<br>/gate/random/setEngineSeed auto<br>/gate/application/start</div></blockquote><div><br></div><div>WORLD.MAC</div><div><br></div><blockquote><div>/gate/world/geometry/setXLength 30 um<br>/gate/world/geometry/setYLength 30 um<br>/gate/world/geometry/setZLength 30 um<br>/gate/world/setMaterial Air<br><br>/gate/world/daughters/name cell<br>/gate/world/daughters/insert sphere<br>/gate/cell/geometry/setRmin 0.0 mm<br>/gate/cell/geometry/setRmax 10 um<br>/gate/cell/placement/setTranslation 0 0 0 um<br>/gate/cell/setMaterial G4_WATER<br>/gate/cell/vis/setVisible 1<br>/gate/cell/vis/setColor blue<br>/gate/cell/vis/forceSolid false<br> <br><br>/gate/cell/daughters/name NP<br>/gate/cell/daughters/insert sphere<br>/gate/NP/geometry/setRmin 0 mm<br>/gate/NP/geometry/setRmax 0.5 um<br>/gate/NP/placement/setTranslation 0 0 0 mm<br>/gate/NP/setMaterial AGuIX_bis<br><br>/gate/NP/repeaters/insert cubicArray<br>/gate/NP/cubicArray/setRepeatNumberX 30<br>/gate/NP/cubicArray/setRepeatNumberY 30<br>/gate/NP/cubicArray/setRepeatNumberZ 30<br>/gate/NP/cubicArray/setRepeatVector 5 5 5 nm</div></blockquote><div><br></div><div>PHYSICS.MAC</div><blockquote><div><br>/gate/physics/addPhysicsList QGSP_BERT_EMV</div><div><br>/gate/physics/Gamma/SetCutInRegion world 50 nm<br>/gate/physics/Electron/SetCutInRegion world 50 nm<br><br>/gate/physics/Gamma/SetCutInRegion cell 20 nm<br>/gate/physics/Electron/SetCutInRegion cell 20 nm<br><br>/gate/physics/Gamma/SetCutInRegion NP 0.5 nm<br>/gate/physics/Electron/SetCutInRegion NP 0.5 nm<br><br>/gate/random/setEngineName MersenneTwister <br><br>/gate/physics/addAtomDeexcitation<br><br>/gate/physics/addProcess PhotoElectric gamma<br>/gate/physics/processes/PhotoElectric/setModel LivermoreModel<br>/gate/physics/processes/PhotoElectric/setAugerElectron true<br>/gate/physics/processes/PhotoElectric/setDeltaRayCut 10 eV<br>/gate/physics/processes/PhotoElectric/setXRayCut 10 eV<br>/gate/physics/processes/PhotoElectric/setStepFunction e- 0.2 0.1 nm<br><br>/gate/physics/addProcess Compton gamma<br>/gate/physics/processes/Compton/setModel LivermoreModel<br>/gate/physics/processes/Compton/setStepFunction e- 0.2 0.1 nm<br><br>/gate/physics/addProcess RayleighScattering<br>/gate/physics/processes/RayleighScattering/setModel LivermoreModel<br><br>/gate/physics/addProcess GammaConversion<br>/gate/physics/processes/GammaConversion/setModel LivermoreModel<br><br>/gate/physics/addProcess ElectronIonisation<br>/gate/physics/processes/ElectronIonisation/setModel LivermoreModel e-<br>/gate/physics/processes/ElectronIonisation/setModel PenelopeModel e+<br>/gate/physics/processes/ElectronIonisation/setStepFunction e- 0.2 0.1 nm<br><br>/gate/physics/addProcess Bremsstrahlung e-<br>/gate/physics/addProcess Bremsstrahlung e+<br>/gate/physics/processes/Bremsstrahlung/setModel LivermoreModel e-<br>/gate/physics/processes/Bremsstrahlung/setModel PenelopeModel e+<br><br>/gate/physics/addProcess eMultipleScattering e-<br>/gate/physics/addProcess eMultipleScattering e+<br>/gate/physics/processes/eMultipleScattering/setModel UrbanModel e-<br>/gate/physics/processes/eMultipleScattering/setModel UrbanModel e+<br><br>/gate/physics/SetMinKineticEnergyInRegion world 1 eV<br>/gate/physics/SetMinKineticEnergyInRegion cell 1 eV<br>/gate/physics/ActivateSpecialCuts gamma</div></blockquote><div><br></div><div>DETECTOR.MAC</div><div><br></div><blockquote><div>/gate/actor/addActor DoseActor dose<br>/gate/actor/dose/save output/dose1.hdr<br>/gate/actor/dose/attachTo cell<br>/gate/actor/dose/stepHitType random<br>/gate/actor/dose/setPosition 0.0 0.0 0.0 mm<br>/gate/actor/dose/setSize 20 20 20 um<br>/gate/actor/dose/setResolution 400 400 400<br>/gate/actor/dose/saveEveryNSeconds 30</div></blockquote><div><br></div><div>SOURCE.MAC</div><div><br></div><blockquote><div>/gate/source/addSource mybeam gps<br>/gate/source/mybeam/gps/particle gamma<br>/gate/source/mybeam/gps/ene/type User<br>/gate/source/mybeam/gps/hist/type energy<br>/gate/source/mybeam/setActivity 300000. becquerel</div><div><br><br>[histogram]<br><br>/gate/source/mybeam/gps/position 0 0 15 um<br>/gate/source/mybeam/gps/pos/type Volume<br>/gate/source/mybeam/gps/pos/shape Cylinder<br>/gate/source/mybeam/gps/pos/inner_radius 0 mm<br>/gate/source/mybeam/gps/pos/radius 10 um<br>/gate/source/mybeam/gps/pos/halfz 0.01 um<br>/gate/source/mybeam/gps/ang/type beam2d<br></div><div><br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div></blockquote><div>Thank you for your help,</div><div><br data-mce-bogus="1"></div><div>Sarah Blind<br><br><br><br><br> <br><br><br></div><div><br></div></div></body></html>