A certain beta-decay process has three components, with maximum energies 0.672, 0.536, and 0.256 MeV. The first component has two coincident y rays: 0.468 and 0.316 MeV, which are also coincident with each other. The second component has coincident y's of 0.604, 0.308, 0.136, 0.468, 0.612, 0.296, and 0.316 MeV. The third beta component is in coincidence with all of the above, plus 0.885, 0.589, 0.416, and 0.280 MeV. Use this information to construct a decay scheme and find the mass difference between the nuclear ground states.