The problem of saturation is exacerbated by the double detectors used on the BCS. During construction, constraints on mass and volume required that the two channels on a spectrometer shared the same detector gas volume. Although the anode signals from the detectors (which allow energy discrimination) are processed separately for each channel, the positional information is provided by a wedge-and-wedge pattern that is shared by the channels. Thus, the processing deadtime for position encoding for a detector is affected by the sum of the total count rates for both channels of that detector.
That the onset of saturation is determined by the counts in two channels can produce ``interesting'' effects. For instance, if the flare is hot, the detector of spectrometer BCS-B will saturate at a higher count rate in Ca XIX (channel 3) than if it is cool. Normally the count rate in S XV (channel 4) will dominate in BCS-B, but for a hot flare the saturation will depend more on the Ca XIX than on the S XV count rate. In spectrometer BCS-A, Fe XXVI (channel 1) has only been observed in a few flares because often the count rate in Fe XXV (channel 2) is already very high by the time that Fe XXVI is likely to be observed.
It should be noted that adjusting the SCA values does not affect the onset of saturation. The same number of photons are still entering the detector and each is seen by the positional encoding circuitry no matter how many are gated as having valid energies.