Seven matched bolometers for millimeter wave observations

We have fabricated a millimeter wave observation system using an array of bolometric detectors. The performance of the system depends largely on obtaining identical performance from each bolometer. We achieved a variance in the responsivity of less than 4% except for one of the seven elements. The bolometers had an electrical NEP of 1.3×10^-16 W/√Hz under radiation background loading of 30pW. We used an AC bridge readout circuit to significantly improve the stability of the array and showed that observations can be done without a mechanical beam switch. The bolometer array is now in use on the Nobeyama 45-m telescope for 150GHz observations.