Reference scans, described in section 4.6.2, ``Reference scans'', and detector memory effects can combine to affect the data produced from band 2 and band 4 detectors during AOT S06 observations.
This possible problem in the flux calibration of S06 science observations is traceable to memory effects left over from reference scans. The intended science objectives may then be compromised in portions of the spectrum.
The document `Possible Detector Memory Effects in SWS Grating range spectra (AOT S06) due to SWS Reference Scans', by K. Leech & P. Morris, 27 May 1997, gives examples of such effects and indicates what to do if they occur.