<html><body><div>Hi, I would like to ask the community if anyone witnessed a difference between the coincidence rate when running the simulation on CPU and GPU? I have got a PET geometry with voxelized phantom and when using CPU, I am getting coincidence output file of size around 700 kb from 1M primaries. When running the same geometry on GPU with the same number of primaries, I am getting files of 2 MB, i.e. + roughly 185 % detected coincidences. Can anyone tell me what can be the cause and how to fix it? I am using those source definitions if that helps: CPU: /gate/source/addSource zdroj voxel /gate/source/zdroj/reader/insert image /gate/source/zdroj/imageReader/translator/insert linear /gate/source/zdroj/imageReader/linearTranslator/setScale 1. Bq /gate/source/zdroj/imageReader/readFile phantom_data/SPECT128.h33 /gate/source/zdroj/setType backtoback /gate/source/zdroj/gps/particle gamma /gate/source/zdroj/gps/energytype Mono /gate/source/zdroj/gps/monoenergy 0.511 MeV /gate/source/zdroj/setPosition -28.2590976 -28.2590976 -28.259072 cm /gate/source/zdroj/gps/angtype iso GPU: /gate/source/addSource zdroj GPUEmisTomo /gate/source/zdroj/attachPhantomTo pacient /gate/source/zdroj/setGPUBufferSize 15000000 /gate/source/zdroj/setGPUDeviceID 1 /gate/source/zdroj/reader/insert image /gate/source/zdroj/imageReader/translator/insert linear /gate/source/zdroj/imageReader/linearTranslator/setScale 1. Bq /gate/source/zdroj/imageReader/readFile phantom_data/SPECT128.h33 /gate/source/zdroj/setType backtoback /gate/source/zdroj/gps/particle gamma /gate/source/zdroj/gps/energytype Mono /gate/source/zdroj/gps/monoenergy 0.511 MeV /gate/source/zdroj/setPosition -28.2590976 -28.2590976 -28.259072 cm /gate/source/zdroj/gps/angtype iso Best regards, Jiri Ters </div></body></html>