HFI performance summary

The essential characteristics of the HFI are gathered in the table below. The HFI has been operating flawlessly for 30 months, the most optimistic expected duration of the helium used by the dilution cooler. [The telescope pointing was achieved with an accuracy of a few arc-seconds. All of the fifty-two bolometers but two collected data in very stable conditions during the whole mission, and practically all of the data was correctly recorded.]

Systematics are now measurable, the most apparent of which being the spikes in the signal produced by cosmic rays hitting the bolometers and their immediate surrounding. [Minute ADC non-linearity revealed by the data scrutiny is being corrected.]

The extreme sensitivity provided by the 100 mK bolometers and the HFI architecture has provided a view of the submillimetre sky with a noise not far from the fundamental limits set by the photon noise of the observed source. In the same time,  The overall sensitivity is finally around that announced as the goal in the "bluebook" (ref bluebook), i.e. twice better than the required sensitivity. One can expect to improve these numbers by about root two when the whole mission data is available.

Beam size and sensitivity for the nominal mission (15 months)

Frequency	100 GHz	143 GHz	217 GHz	353 GHz	545 GHz	857 GHz
Beam size (FWHM, arcmin)	9.66	7.27	5.01	4.86	4.84	4.63
Sensitivity per fiducial pixel	3.95 µK/K	2.35 µK/K	4.58 µK/K	15.17 µK/K	0.013 Mjy/sr	0.013 Mjy/sr
Goal sensitivity	2.5	2.2	4.8	14.7