How QUaD Works


Bolometer temperature coupled to intensity of incoming radiation from small "spots" on the sky
Whole telescope moves (scans), sweeping the set of pencil beams around on the sky
We read out the *changing* bolometer temperature as a function of pointing position - called timestream data...
any change in bolometer temperature appears in readout...
need an outrageously stable system!
Signal is tiny!
Integrate (average down the noise) for 100's of days