Spitzer Documentation & Tools
MIPS Instrument Handbook


7.2.4        Electronic non-linearities

The electronic non-linearities for the MIPS-Ge detectors are corrected for in the online pipeline.  However, spurious electronic non-linearity solutions for a few unstable pixels on the top row of the 70 micron detector can yield artifacts in the mosaics.  The recommended solution is to make sure you have the most recent pmask, and make mosaics with this updated pmask, ignoring these pixels (use the pmask rejection parameter=16648).

7.2.5        Flux non-linearities

The flux nonlinearities for the MIPS-Ge detectors represent the differences in the flux conversion factor as a function of source flux.  Thre pipeline assumes a constant flux conversion factor for all flux ranges.  MIPS 70 micron sources show significant (~40%) flux non-linearities over the range from 22 mJy to 17 Jy, although the use of PSF-fitted photometry rather than aperture photometry greatly reduces this effect (see Gordon et al. 2007, PASP, 119, 1019). The overall behavior of the 160 micron stressed Ge:Ga array is linear between 0.1 and 2 Jy (Stansberry et al 2007, PASP, 119, 1038).  Continuing up to 4 Jy, 160 micron shows a departure of ~10% from linearity for point sources