def METHOD_NAME( ap_mass , lhe, detector ) :
    """Example configuration for producing dark brem interactions in the ECal. 
    This configures the simulator to fire a 4 GeV electron upstream of the 
    tagger tracker.  The electron is allowed to propagate into the ECal where 
    the dark-photon production cross-section is biased up.  Only events that 
    result in a dark-photon being produced in the ECal are kept. 
    Parameters
    ----------
    ap_mass : float
        The mass of the A' in MeV.
    lhe : str
        The path to the LHE file to use as vertices of the dark brem. 
    detector : str
        Path to the detector.
    Return
    ------
    Instance of the simulator configured for dark-brem production in the ECal.
    Example
    -------
    Here we use the example vertex library. This should not be used
    for large (>50k) event samples.
        from LDMX.SimCore import makePath
        eat_ap_sim = eat.dark_brem(1000., makePath.makeLHEPath(1000.), 'ldmx-det-v12')
    """
    sim = simulator.simulator( "ecal_dark_brem_%sMeV" % str(ap_mass) )
    from LDMX.Ecal import EcalGeometry
    sim.description = "One e- fired far upstream with Dark Brem turned on and biased up in ECal"
    sim.setDetector( detector , True )
    sim.generators.append( generators.single_4gev_e_upstream_tagger() )
    sim.beamSpotSmear = [ 20., 80., 0. ] #mm
    #Activiate dark bremming with a certain A' mass and LHE library
    from LDMX.SimCore import METHOD_NAME
    db_model = METHOD_NAME.G4DarkBreMModel( lhe )
    db_model.threshold = 2. #GeV - minimum energy electron needs to have to dark brem
    db_model.epsilon   = 0.01 #decrease epsilon from one to help with Geant4 biasing calculations
    sim.METHOD_NAME.activate( ap_mass , db_model )
    #Biasing dark brem up inside of the ecal volumes
    from LDMX.SimCore import bias_operators
    from math import log10
    sim.biasing_operators = [ 
            bias_operators.DarkBrem.ecal(
                sim.METHOD_NAME.ap_mass**max(2, log10(sim.METHOD_NAME.ap_mass)) / db_model.epsilon**2
              )
            ]
    sim.actions = [
            #Make sure all particles above 2GeV are processed first
            util.PartialEnergySorter(2000.),
            #Abort events if the electron doesn't get to the ECal with 3.5GeV
            filters.PrimaryToEcalFilter(3500.),
            #Only keep events when a dark brem happens in the Ecal
            filters.EcalDarkBremFilter(2000.)
    ]
    return sim