  We present radio-frequency thermometry based on a tunnel junction between a
superconductor and proximitized normal metal. It allows operation in a wide
range of biasing conditions. We demonstrate that the standard finite-bias
quasiparticle tunneling thermometer suffers from large dissipation and loss of
sensitivity at low temperatures, whereas thermometry based on zero bias anomaly
avoids both these problems. For these reasons the latter method is suitable
down to lower temperatures, here to about 25 mK. Both thermometers are shown to
measure the same local temperature of the electrons in the normal metal in the
range of their applicability.
