# $Id: detector.py,v 1.3 2003/06/26 11:54:13 dressel Exp $
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# GEANT4 tag $Name:  $
# -------------------------------------------------------------------
#

# A detector is either the of the "simple" or "ring" type.
# the volumina of the "simple" detectors are the same at all
# positions (00, 20, 40 cm off beam axis). The "ring" type detectors
# have different volumina at the different positions.
# For convinience a class Detector is provided to link a detector
# position and it's volume.


d00Volume = 1608.8   # volume of the 12.9 cm x 12.9 cm cyinder
d20Volume = 20268.3  # volume of the ring at 20 cm
d40Volume = 40536.6  # volume of the ring at 40 cm

# map of distances to volumina for the 12.9 cm x 12.9 cm detectors
SimpleDetectorVolume = {"00":d00Volume, "20":d00Volume, "40":d00Volume}
# map of distances to volumina for ring detectors
RingDetectorVolume = {"00":d00Volume, "20":d20Volume, "40":d40Volume}

# map of detector type to distance-volumina map
DetectorVolume = {"simple":SimpleDetectorVolume,
                  "ring"  :RingDetectorVolume}


# the area of the beam pipe needed for scaling
beamPipeArea = 93.31

# the source detector volume: beamPipeArea * 0.1 cm
sourceDetectorVolume = 9.33

# source flux from the TIARA paper
Fexp43_Coli = 1.76E+04
Fexp43 = 1.94E+04
Fexp68_Coli = 2.04E+04
Fexp68 = 2.46E+04



class Detector(object):
    "Distance and volume of a Detector."
    def __init__(self, dist, detType):
        self.name = dist
        self.volume = DetectorVolume[detType][dist]





# function to calculate the scale factor

def detScale(ngen, energy, coli):
    """Detrmine scale.

    Determine scale according to the number of generated neutrons,
    the proton beam energy. If coli == 1, the flux at the
    colimator exit is used, else the flux at 401 cm is used.
    """
    Asrc = beamPipeArea
    Fexp = 0
    if energy == "43":
        if coli == 1:
            Fexp = Fexp43_Coli
        else:
            Fexp = Fexp43
    else:
        if energy == "68":
            if coli == 1:
                Fexp = Fexp68_Coli
            else:
                Fexp = Fexp68

    S = Fexp * Asrc / ngen

    return S