use DecayInFlight generator by default

Generators/DIFGenerator/python/DIFSampler.py

@@ -5,7 +5,7 @@
 import ParticleGun as PG
 from math import sqrt, sin, cos, acos
 from random import uniform
-from AthenaCommon.SystemOfUnits import TeV, MeV
+from AthenaCommon.SystemOfUnits import TeV, GeV, MeV
 from AthenaCommon.PhysicalConstants import pi
 from ROOT import TLorentzVector
 
@@ -90,7 +90,10 @@ 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 = CylinderSampler([0, 100**2],[0, 2*pi],[-1500, 0],0)):
+    # 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)):
+    def __init__(self, daughter1_pid=13, daughter2_pid=-13, mother_pid=None,
+                 mother_mom=PG.EThetaMPhiSampler([sqrt((10*GeV)**2 + (500*MeV)**2), sqrt((1*TeV)**2 + (500*MeV)**2)], [0, 0.015], 500*MeV, [0, 2*pi]),
+                 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)

Generators/FaserParticleGun/python/FaserParticleGunConfig.py

@@ -141,7 +141,7 @@ def FaserParticleGunDecayInFlightCfg(ConfigFlags, **kwargs) :
     return cfg
 
 def FaserParticleGunCfg(ConfigFlags) :
-    generator = ConfigFlags.Sim.Gun.setdefault("Generator", "SingleParticle")
+    generator = ConfigFlags.Sim.Gun.setdefault("Generator", "DecayInFlight")
     kwargs = ConfigFlags.Sim.Gun
     if generator == "SingleEcalParticle" :
         return FaserParticleGunSingleEcalParticleCfg(ConfigFlags, **kwargs)