Fig. (7) The uppermost part of the tritium β spectrum, wide only 7 meV, was calculated for the normal hierarchy of the neutrino mass states (m₁ < m₂ < m₃) assuming the endpoint energy E₀ = 18.575 keV and m₁ = 200 meV. The same mass square differences and the admixtures |U_ei|² as in Fig. (1) were assumed. Under these assumptions m₂ = 200.19 meV, m₃ = 206.19 meV, and the relative intensities of partial spectra β₁, β₂ and β₃ are |U_e1|² = 0.6803, |U_e2|² = 0.2354 and |U_e3|² = 0.0843, respectively [8]. The experimentally observable β-spectrum is composed of the three components. Taken with sufficiently high instrumental resolution, the spectrum will exhibit kinks at energies E₀ – m_i (i = 2, 3). In our example, the average electron neutrino mass m_ve defined by Eq. (5) equals 200.57 meV. We have assumed for simplicity that all the ³H → ³He + e^- + ͞ν_e decays proceed to the ground state of the daughter ion.