Need help to create coincidence spectra

Geatn4 based Co-axial HPGe detector (yes. of course, Ge is not bare is surrounded by external C-fiber, Cu, Al/Mylar etc but active volume is Ge only. ). Here single Ge detector is made of two parts first disc and second hollow cylinder.

In the model of four HPGe detector is kept, in a manner like “plus sign(+)”. Each vortex is detector and at the point of intersection source is kept.

Now, I am generating gamma events randomly using Geant4 gps in all four pi direction. The event detected and their energy deposited on each detector is can be called as “singles Spectra”. Similarly, If any two events detected simultaneously in two opposite detector is called “Coincidence spectra”.

The way I am collecting singles spectra in stepping action is as follows

if(name==" D1physicalDetector_Ge “||name==” D1physicalDetector_Ge1 ")//
if (EdepStep ==0.) return;
if (EdepStep > 0.) eventAction->addEdepTotal(EdepStep);

Similarly, for coincidence spectra

if((name==" D1physicalDetector_Ge “||name==” D1physicalDetector_Ge1 “)&&name==” D3physicalDetector_Ge “||name==” D3physicalDetector_Ge1 “)//
if (EdepStep ==0.) return;
if(name==” D1physicalDetector_Ge “||name==” D1physicalDetector_Ge1 “)
{ if (EdepStep > 0.) eventAction->addEdepTotal5(EdepStep);}
else if(name==” D3physicalDetector_Ge “||name==” D3physicalDetector_Ge1 ")
{ if (EdepStep > 0.) eventAction->addEdepTotal6(EdepStep);}

But, the problem is,with this method I am not getting anything in coincidence spectra.

I request you to look at it guide me.

In the stepping action you are checking if the step is happening in two different volumes simultaneously, which is impossible. You have to collect the energy deposition in each detector (and the time of the deposition, if needed) and check at the end of the event if a coincidence happened.

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