def bowtie_filter(cfg):
'''
Apply the transmittance of bowtie filter, dim: [Ebin, totalNumCells]
'''
if not cfg.protocol.bowtie:
return cfg
# find bowtie file
bowtieFile = cfg.protocol.bowtie
if not os.path.isfile(bowtieFile):
bowtiePath = get_path().bowtie + "/"
if os.path.isfile(bowtieFile + ".dat"):
bowtieFile += ".dat"
elif os.path.isfile(bowtiePath + bowtieFile):
bowtieFile = bowtiePath + bowtieFile
elif os.path.isfile(bowtiePath + bowtieFile + ".dat"):
bowtieFile = bowtiePath + bowtieFile + ".dat"
else:
raise Exception("Cannot find bowtie file: %s or %s.dat" %
(bowtieFile, bowtieFile))
# read bowtie file
data = np.loadtxt(bowtieFile, dtype=np.single, comments=['#', '%'])
gammas0 = data[:, 0]
t0 = data[:, 1:] # thickness in cm
bowtieMaterials = ['al', 'graphite', 'cu', 'ti']
Evec = cfg.spec.Evec
gammas1 = cfg.det.gammas
muT = 0
for i in range(len(bowtieMaterials)):
mu = GetMu(bowtieMaterials[i], Evec)
f = interpolate.interp1d(gammas0,
t0[:, i],
kind='linear',
fill_value='extrapolate')
t1 = f(gammas1) / cfg.det.cosAlphas
muT += t1 @ mu.reshape(1, len(mu))
trans = np.exp(-muT)
cfg.src.filterTrans *= trans
return cfg
def flat_filter(cfg):
'''
Apply the transmittance of flat filter at source side, dim: [Ebin, totalNumCells]
'''
cosineFactors = 1/cfg.det.cosGammas/cfg.det.cosAlphas
Evec = cfg.sim.Evec
trans = np.ones([cfg.det.totalNumCells, cfg.spec.nEbin], dtype = np.single)
if hasattr(cfg.protocol, "flatFilter"):
for ii in range(0, round(len(cfg.protocol.flatFilter)/2)):
material = cfg.protocol.flatFilter[2*ii]
depth = cfg.protocol.flatFilter[2*ii+1]
mu = GetMu(material, Evec)
trans *= np.exp(-depth*0.1*cosineFactors @ mu.reshape(1, mu.size))
cfg.src.filterTrans *= trans
return cfg