Cas A Energy Spectra in 1993 and 1998
The figure below compares the energy spectra of Cas A obtained in
1993 August and 1998 July.
The two energy spectra were obtained at the same pointing position
and with the same observation mode (1 ccd faint mode).
The energy spectrum in 1993 was corrected for dfe, echo and CTE.
In addition to these correction, RDD correction was applied to the
data in 1998.
Thus the difference of the energy spectra is considered to be
due to the non-uniform CTE.
Note that the CTE correction applied here assumes that the CTE is
a linear function of the number of charge transfer.
Therefore, effects of column to column variations of the CTE are
remained even after the CTE correction.