from .Constants import fine_structure_constant, m_electron
try:
from ROOT import TMath
except ImportError:
pass
[docs]def DiracFermiFunction(E, Z, m):
beta = TMath.Sqrt(2 * E / m)
eta = fine_structure_constant() * (Z + 1) / beta
return 2 * TMath.Pi() * eta / (1 - TMath.Exp(-2 * TMath.Pi() * eta))
[docs]def RFactor(E, Z):
# Form factor to use to define the spectrum shape
# Use this for defining the Kurie plot
return DiracFermiFunction(E, Z, m_electron()) * TMath.Sqrt(2 * m_electron() * E) * (E + m_electron());
[docs]def TritiumSpectrumShape(E, E0, Z, mbeta):
return RFactor(E, Z) * (E0 - E) * TMath.Sqrt(TMath.Power(E0 - E, 2) - TMath.Power(mbeta, 2));