  We investigated the temperature dependence of the density-of-states in the
iron-based superconductor SmO_1-xF_xFeAs (x=0, 0.12, 0.15, 0.2) with high
resolution angle-integrated photoemission spectroscopy. The density-of-states
suppression is observed with decreasing temperature in all samples, revealing
two characteristic energy scales (10meV and 80meV). However, no obvious doping
dependence is observed. We argue that the 10meV suppression is due to an
anomalously doping-independent normal state pseudogap, which becomes the
superconducting gap once in the superconducting state; and alert the
possibility that the 80meV-scale suppression might be an artifact of the
polycrystalline samples.
