Primary thermometry by the measurement of shot noise in a tunnel junction

We fabricated an Al-AlO
x
-Al tunnel junction by the double-angle evaporation technique as a source of shot noise. A precision RF-power-measurement setup in the frequency range near 1 GHz was installed in a He-3 refrigerator. We measured temperature from 0.3 K to room temperature using shot noise thermometer and compared the temperature with that of conventional temperature sensors.