Fix DIF decay position and typo in Calo code

Calorimeter/FaserCaloSimEvent/src/CaloHitIdHelper.cxx

@@ -45,7 +45,7 @@ void CaloHitIdHelper::Initialize() {
   const EcalID* pix;
   ServiceHandle<StoreGateSvc> detStore ("DetectorStore", "CaloHitIdHelper");
   if (detStore.retrieve().isSuccess()) {
-    if (detStore->retrieve(pix, "Ecal_ID").isFailure()) { pix = 0; }
+    if (detStore->retrieve(pix, "EcalID").isFailure()) { pix = 0; }
   }
 
   InitializeField("Row", 0, 1);

Generators/DIFGenerator/README.md

@@ -12,7 +12,7 @@ Options available through the `DIFSampler` constructor include:
 * daughter2_pid - The pid of the second decay particle. The default valid pids are listed [here](https://gitlab.cern.ch/atlas/athena/-/blob/master/Generators/ParticleGun/python/samplers.py#L825). (default: -11)
 * mother_pid - The pid of the mother particle. Only set this if you need to get the mother's pid from the mother_sampler property (default: None)
 * mother_mom - A momentum sampler representing the mother particle's momentum. (default: PG.EThetaMPhiSampler(sqrt((1 * TeV)**2 + (10 * MeV)**2),0,10*MeV,0))
-* mother_pos - A position sampler representing the mother particle's position. (default: PG.PosSampler(0,0,[-1500,0],0))
+* mother_pos - A position sampler representing the mother particle's position. (default: DIFGenerator.CylinderSampler(rsq = [0, (100*mm)**2], phi = [0,2*pi], z = [-1500*mm,0]))
 
 The pid, momentum sampler, and position sampler of the mother particle can be modified after initialization by setting the `mother_sampler` property of the `DIFSampler`. The `mother_sampler` property should be a [ParticleSampler](https://gitlab.cern.ch/atlas/athena/-/blob/master/Generators/ParticleGun/python/samplers.py#L858).
 

Generators/DIFGenerator/python/DIFSampler.py

@@ -7,6 +7,58 @@ from math import sqrt, sin, cos, acos
 from random import uniform
 from AthenaCommon.SystemOfUnits import TeV, MeV
 from AthenaCommon.PhysicalConstants import pi
+from ROOT import TLorentzVector
+
+class CylinderSampler(PG.Sampler):
+    """
+    Sampler of position 4-vectors within a cylindrical volume.
+    """
+
+    def __init__(self, rsq, phi, z, t=0):
+        self.rsq   = rsq
+        self.phi = phi
+        self.z   = z
+        self.t   = t
+
+    @property
+    def rsq(self):
+        "rsq position sampler"
+        return self._rsq
+    @rsq.setter
+    def rsq(self, rsq):
+        self._rsq = PG.mksampler(rsq)
+
+    @property
+    def phi(self):
+        "phi position sampler"
+        return self._phi
+    @phi.setter
+    def phi(self, phi):
+        self._phi = PG.mksampler(phi)
+
+    @property
+    def z(self):
+        "z position sampler"
+        return self._z
+    @z.setter
+    def z(self, z):
+        self._z = PG.mksampler(z)
+
+    @property
+    def t(self):
+        "Time sampler"
+        return self._t
+    @t.setter
+    def t(self, t):
+        self._t = PG.mksampler(t)
+
+    def shoot(self):
+        r   = sqrt(self.rsq())
+        phi = self.phi()
+        z   = self.z()
+        t   = self.t()
+        #print "POS =", x, y, z, t
+        return TLorentzVector(r * cos(phi), r * sin(phi), z, t)
 
 class DIFSampler(PG.ParticleSampler):
     """
@@ -38,8 +90,8 @@ class DIFSampler(PG.ParticleSampler):
             else:
                 self.mom = None
 
-    def __init__(self, daughter1_pid = 11, daughter2_pid = -11, mother_pid = None, mother_mom = PG.EThetaMPhiSampler(sqrt((1*TeV)**2 + (10*MeV)**2),0,10*MeV,0),mother_pos = PG.PosSampler(0,0,[-1500,0],0)):
-        self._mother_sampler = PG.ParticleSampler(mother_pid,mother_mom,mother_pos)
+    def __init__(self, daughter1_pid = 11, daughter2_pid = -11, mother_pid = None, mother_mom = PG.EThetaMPhiSampler(sqrt((1*TeV)**2 + (10*MeV)**2),0,10*MeV,0),mother_pos = CylinderSampler([0, 100**2],[0, 2*pi],[-1500, 0],0)):
+        self._mother_sampler = PG.ParticleSampler(pid = mother_pid, mom = mother_mom, pos = mother_pos)
 
         self.daughter1 = self.particle(daughter1_pid)
         self.daughter2 = self.particle(daughter2_pid)

Simulation/G4Faser/G4FaserAlg/test/runG4DecayInFlight.py

@@ -66,6 +66,8 @@ if __name__ == "__main__":
     ConfigFlags.Detector.GeometryPreshower   = True
     ConfigFlags.Detector.SimulateFaserSCT   = True
     ConfigFlags.Detector.GeometryFaserSCT   = True
+    ConfigFlags.Detector.SimulateEcal = True
+    ConfigFlags.Detector.GeometryEcal = True
     ConfigFlags.Detector.SimulateUpstreamDipole = True
     ConfigFlags.Detector.SimulateCentralDipole = True
     ConfigFlags.Detector.SimulateDownstreamDipole = True
@@ -74,6 +76,12 @@ if __name__ == "__main__":
     ConfigFlags.Detector.GeometryDownstreamDipole = True
     ConfigFlags.GeoModel.Align.Dynamic  = False
     ConfigFlags.Sim.ReleaseGeoModel     = False
+
+#
+# Physics list
+#
+
+    ConfigFlags.Sim.PhysicsList = "FTFP_BERT"
 #
 # All flags should be set before calling lock
 #
@@ -89,8 +97,13 @@ if __name__ == "__main__":
     pg = PG.ParticleGun()
     pg.McEventKey = "GEN_EVENT"
     pg.randomSeed = 123456
-
     pg.sampler = DIFSampler()
+# Next line sets the range of mother particle energies to [0.1 TeV, 0.2 TeV] (default is 1 TeV)
+#   pg.sampler.mother_sampler.mom.energy = [0.1*TeV, 0.2*TeV]
+# Next line sets the range of cylindrical radii to [90 mm, 100 mm] (default is [0, 100 mm])
+#   pg.sampler.mother_sampler.pos.rsq = [90**2, 100**2]
+# Next line changes the range of z vertex positions to [-1000 mm, -500 mm] (default is [-1500 mm, 0])
+#   pg.sampler.mother_sampler.pos.z = [-1000, -500]
     acc.addEventAlgo(pg, "AthBeginSeq") # to run *before* G4
 #
 # Only one of these two should be used in a given job
@@ -108,7 +121,8 @@ if __name__ == "__main__":
                               "McEventCollection#TruthEvent",
                               "McEventCollection#GEN_EVENT",
                               "ScintHitCollection#*",
-                              "FaserSiHitCollection#*"
+                              "FaserSiHitCollection#*",
+                              "CaloHitCollection#*"
                             ], disableEventTag=True))
     acc.getEventAlgo("OutputStreamHITS").AcceptAlgs = ["G4FaserAlg"]               # optional
     acc.getEventAlgo("OutputStreamHITS").WritingTool.ProcessingTag = "StreamHITS"  # required