As mentioned yesterday, because of a conflict between XFEL DAQ and the timing of the current source scans, it is not possible to take dynamic range scans here at XFEL for the time being. As a consequence, this means that we cannot measure or calculate the pedestals of medium and low gain.

Therefore, we decided to test, if it is possible to switch gain during the integration time in order to get the pedestal for medium and low gain.

For MG:

  • EGSGAT has to to be changed from 14 to 2
  • G1SGAT has to be changed from 16 to 4

For LG:

  • Changes for MG plus
  • G2SGAT has to be changed from 15 to 3


Please note that the point we obtain here is the interception point on the y-axis of the dynamic range scan.

Since we force gain switching here without charge an offset between the extrapolated interseption point and the point obtained from this measurement is expected but has to be investigated in more detail.



Below you see histograms of analog and digital data for module index 5 (Q2M2). (Module index given in the title of the plots is wrong)

Data location

Test data for implementation into calibration infrastructure can be found here:

/gpfs/exfel/exp/SPB/201730/p900009/raw/

HG: r0428

MG: r0429

LG: r0430