ACIS gain @ -120C page

Monitoring and analysis of ACIS gain by the instrument team. In all cases the focal plane temperature is -120C and the gain is measured using the Al-K (1.5 keV), Ti-Kα (4.5 keV) and Mn-Kα (5.9 keV) lines from the bottom 20 rows of the CCD (to avoid the effects of CTI). The numbers for each CCD are an average over all nodes.

Pulseheight (ADU) = Slope (ADU/eV) x Energy (eV) + Offset (ADU)

Also shown in these figures is the gain measured during OAC with the ICM and FCM sources. The ICM (dotted line) illuminates only part of S2 and S3 when the ACIS door is closed. During that period the focal plane temperature was -120C. The FCM data (dashed line) was collected at -90C.

Updated monthly.

More description of these data can be found in ACIS Memo #195.

The data used to make these plots can be found here

Gain slope (ADU/eV)

• 04/03/07 - Temperature filter upper limit changed from -119.7 to -119 which increases the number of data points for 2005 and beyond.