{
	// uncomment as you go along for each step of the exercises

/*
	// energy with and without Compton scatters in the phantom
	Singles->Draw("energy");
	Singles->SetFillColor(kBlue); 
	Singles->Draw("energy","comptonPhantom<1", "same");
	Singles->SetFillColor(kRed); 
	Singles->Draw("energy","comptonPhantom>0", "same");
*/
/*
    // source position for coincidences
	Coincidences->Draw("sourcePosZ1:sourcePosZ2","","colz");
*/

	// distance between detected gammas
	Coincidences->Draw("sqrt((globalPosX1-globalPosX2)**2 + (globalPosY1-globalPosY2)**2 + (globalPosZ1-globalPosZ2)**2)");
	Coincidences->SetFillColor(kRed);
	Coincidences->Draw("sqrt((globalPosX1-globalPosX2)**2 + (globalPosY1-globalPosY2)**2 + (globalPosZ1-globalPosZ2)**2)","comptonPhantom1+comptonPhantom2>0","same");
/*
 	// acollinearity angle
	Coincidences->Draw("180./3.1415927*acos((globalPosX1*globalPosX2+globalPosY1*globalPosY2+globalPosZ1*globalPosZ2)/(sqrt(globalPosX1**2+globalPosY1**2+globalPosZ1**2)*sqrt(globalPosX2**2+globalPosY2**2+globalPosZ2**2)))");
	Coincidences->SetFillColor(kRed);
	Coincidences->Draw("180./3.1415927*acos((globalPosX1*globalPosX2+globalPosY1*globalPosY2+globalPosZ1*globalPosZ2)/(sqrt(globalPosX1**2+globalPosY1**2+globalPosZ1**2)*sqrt(globalPosX2**2+globalPosY2**2+globalPosZ2**2)))","comptonPhantom1+comptonPhantom2<1.","same");
*/
}