  Quantum computing relies on the operation of qubits in an environment as free
of noise as possible. This work reports on measuring the impact of
environmental radiation on lifetimes of fixed frequency transmon qubits with
various capacitor pad geometries by varying the amount of shielding used in the
measurement space. It was found that the qubit lifetimes are robust against
these shielding changes until the most extreme limit was tested without a
mixing chamber shield in the refrigerator. In contrast, the quasiparticle
tunneling rates were found to be extremely sensitive to all configurations
tested, indicating these devices are not yet limited by losses related to
superconducting quasiparticles.
