  We characterize a superconducting qubit before and after embedding it along
with its package in an absorptive medium. We observe a drastic improvement in
the effective qubit temperature and over a tenfold improvement in the
relaxation time up to 5.7 $\mu$s. Our results suggest the presence of external
radiation inside the cryogenic apparatus can be a limiting factor for both
qubit initialization and coherence. We infer from simple calculations that
relaxation is not limited by thermal photons in the sample prior to embedding,
but by dissipation arising from quasiparticle generation.
