HPGe BGO Hit Pattern

[cnatzke]

I've been trying to build a HPGe BGO hit pattern that resembles the image blow except that it includes the BGO channels.

I emailed Vinzenz and he suggested I transcribe the reply here so others can benefit and suggest alternate solutions.

This should be very easy, whether you use the analysis tree directly or a selector. If you plot this directly from the analysis tree, you will need to essentially "build" your own array number as this is a property of TGriffinHits and not TDetectorHits. So use something like
AnalysisTree->Draw("4*(TGriffin.fHits.GetDetector()-1)+TGriffin.fHits.GetCrystal()+1:20*(TGriffinBgo.fHits.GetDetector()-1)+5*TGriffinBgo.fHits.GetCrystal()+TGriffinBgo.fHits.GetSegment()","","colz")
Of course in a selector you can just loop over TGriffin and TGriffinBgo, get the hits directly as TGriffinHits or TGriffinBgoHits and use their GetArrayNumber functions to plot.

To simplify even further the command TGriffin.fHits.GetArrayNumber():TGriffinBgo.fHits.GetArrayNumber() in the Draw() command also works.

[cnatzke]

@VinzenzBildstein Does this loop structure make sense? I'm assuming a bgo hit does not have a GetSuppressedMultiplicity correct?

        // suppressed histograms
        for (auto g1 = 0; g1 < fGrif->GetSuppressedMultiplicity(fGriffinBgo); g1++) {
            auto grif_hit1 = fGrif->GetSuppressedHit(g1);
            ...
            for (auto b1 = 0; b1 < fGriffinBgo->GetMultiplicity(); b1++) {
                auto bgo_hit1 = fGriffinBgo->GetHit(b1);
                // 1D
                // 2D
                hist_2D["grif_bgo_hitpattern"]->Fill(grif_hit1->GetArrayNumber(), bgo_hit1->GetArrayNumber());
            } // end Bgo
        } // end suppressed

[VinzenzBildstein]

You might want to cast the bgo hit to a TGriffinBgoHit*, otherwise the GetArrayNumber() might not work. And if you loop over suppressed hits only be aware that the hit pattern you get will not include any BGOs next to the crystal that was hit (as those hits are suppressed). If that't what you want, use it this way, otherwise use a normal loop over all single hits of GRIFFIN.

[cnatzke]

otherwise use a normal loop over all single hits of GRIFFIN.

I did this earlier in the code, I just wanted to double check my logic for this loop.

What is the default suppression scheme? That a BGO will suppress all four HPGe of that clover, or that blue BGO only suppress Blue HPGe etc.?

[cnatzke]

This line now causes a seg-fault:

            for (auto b1 = 0; b1 < fGriffinBgo->GetMultiplicity(); b1++) {
                TGriffinBgoHit* bgo_hit1 = dynamic_cast<TGriffinBgoHit*>(fGriffinBgo->GetHit(b1));

I had to add #include TGriffinBgoHit.h to the top of the file. Did I cast the variable incorrectly?

[VinzenzBildstein]

That's weird, what error message do you get from the segfault? I personally would have used a static_cast instead of dynamic_cast, maybe try that.

[cnatzke]

Changing to static_cast fixed it. It must have something to do with how TGriffinBgoHit is inherited but that starts to get beyond my C++ experience.

[VinzenzBildstein]

I'm not really sure why the dynamic_cast creates a seg-fault, but it can return a null pointer (which would create a seg-fault like error).