Sorry I forgot to attach the test bench result in the former email, here it is. Hi, Recently I installed the new version of the GATE v3.0 into my computer with Geant4.8.0.p01, CLHEP2.0.2.2, and the compiler is gcc4.0.1 and the Linux version is Scientific Linux CERN. After I installed the GATE, I ran the test bench of the PET and the result is shown here as the attachment. From the result, you will see there are only 7 sectors in the detector ring, which should be 8. Then I checked with my own camera geometry and every time the sector numbers was short of 1 as what I have defined. I checked the source code of GATE and find such code in GateAngularRepeater.cc . . . void GateAngularRepeater::PushMyPlacements(const G4RotationMatrix& currentRotationMatrix,                                                          const G4ThreeVector& currentPosition,                                                          G4double ) {   G4double dphi ;   if ( m_angularSpan == 360. *deg)   dphi = GetAngularPitch_1();   if ( m_angularSpan != 360. *deg)   dphi = GetAngularPitch_2(); . . . I think that the comparision of two float type like this ( m_angularSpan == 360. *deg) is dangeous, sometimes it works fine but sometimes it may give wrong result based on what kind of compiler, system or cpu are used. So I changed the code as this:   if ( m_angularSpan < 360.0005 *deg &&  m_angularSpan > 359.9995 *deg)   dphi = GetAngularPitch_1();   else   dphi = GetAngularPitch_2(); After recompile the Gate, now the result seems ok. I also checked the old versions of GATE, they were all coded in the same way and I didn't have this problem before. So I think it mostly caused by the different compiler (gcc4). This just a reminder to you if you have the same proble in your computer. Yuxuan