  We fabricate graphene-TiOx-Al tunnel junctions and characterize their radio
frequency response. Below the superconducting critical temperature of Al and
when biased within the superconducting gap, the devices show enhanced dynamic
resistance which increases with decreasing temperature. Application of radio
frequency radiation affects the dynamic resistance through electronic heating.
The relation between the electron temperature rise and the absorbed radiation
power is measured, from which the bolometric parameters, including heat
conductance, noise equivalent power and responsivity, are characterized.
