An AC bridge readout for bolometric detectors

The authors have developed a bolometer readout circuit which dramatically improves the low frequency stability of bolometric detectors. In astronomical applications, the readout allows for qualitatively different observation modes (e.g. staring or slow drift scanning) which are particularly well suited for space observations and for the use of arrays. In many applications the new readout can also increase sensitivity. The authors present noise spectra for /sup 4/He temperature bolometers with no excess noise at frequencies greater than 0.1 Hz. The optical responsivity of a bolometer operated with the new readout is measured to be the same as that of the bolometer operated with a conventional readout