The secondary-electron-emission spectrum has been measured for diamond (110) type 2{ital a}. Peaks at 6, 14.4, and 22.9 eV with respect to the top of the valence band were observed. The 6-eV peak was associated with the conduction-band minimum, whereas the 14.4- and 22.9-eV peaks were associated with electronic transitions to higher conduction bands. These peak assignments were found to be in very good agreement with other spectroscopic techniques sensitive to the density of empty states above the vacuum level, and to band-structure calculations.