'''
Some constants useful for various things...
'''
[docs]def m_electron(): return 510998.910 # Electron mass in eV
[docs]def hbar(): return 6.582119514e-16 # Reduced Planck's constant in eV*s
[docs]def c() : return 299792458. # Speed of light in m/s
[docs]def hbarc(): return hbar() * c() # hbar * c
[docs]def omega_c(): return 1.758820088e+11 # Angular gyromagnetic ratio in rad Hz/Tesla
[docs]def freq_c(): return omega_c()/(2. * ROOT.TMath.Pi()) # Gyromagnetic ratio in Hz/Tesla
[docs]def k_boltzmann(): return 8.61733238e-5 # Boltzmann's constant in eV/Kelvin
[docs]def unit_mass() : return 931.494061e6 # Unit mass in eV
[docs]def seconds_per_year(): return 365.25 * 86400.
[docs]def fine_structure_constant(): return 0.0072973525664 # fine structure constant (no unit)
# Tritium-specific constants
[docs]def tritium_rate_per_eV(): return 2.0e-13 # fraction of rate in last 1 eV
[docs]def tritium_atomic_mass(): return 3.016 * unit_mass() # Atomic tritium mass in eV
[docs]def tritium_halflife(): return 12.32 * seconds_per_year() # Halflife of tritium (in seconds)
[docs]def tritium_lifetime(): return tritium_halflife()/0.69314718056 # Lifetime of tritium (in seconds)
[docs]def tritium_endpoint(): return 18.6E+3 # Tritium endpoint value