3.5.1 Saturation of PU arrays with SL

Long integration times with the SL module are potentially at risk of saturating the IRS peak-up arrays during spectroscopic observation, because of the presence of high-background levels near your target. This will likely affect the data, because when one or both of the peak-up arrays have saturated, the IRS pipeline has difficulty establishing the appropriate droop correction for these saturated data. As a result, the final BCD image could have patchy horizontal bands of bright and dark emission. These patterns cannot be easily removed by normal background subtraction.

Users should avoid strongly saturating the peak-up arrays when performing spectroscopic observations. The peak-up arrays (at 16 and 22 microns) will saturate at 500 MJy/sr in 6 seconds, 50 MJy/sr in 60 sec, and 12.5 MJy/sr in 240 sec. However, the current pipeline is set up to handle background levels only up to 25 MJy/sr at 240 sec.