ICID 27 => LED_STABILITY_BINNINGEIGHT

Illumination:

  • LED.

Purpose:

  • LED calibration measurement with binning factor 8 (global).
  • Monitoring of long-term detector stability.
  • Monitoring of bad and dead detector pixels on binned pixels (binning factor 8).

Location:

  • Eclipse side of the orbit.

Usage:

  • From launch onwards, once per week, five times per month.

Description:

LED calibration measurement with binning factor 8 (global). First a number of dark measurements are performed (ICID 26), then a number of light measurements. These binned measurements are well suited to determine / monitor the long-term detector stability over time and the detector bad and dead (binned) pixels. The LEDs turn out to be very stable within one measurement sequence (little drift with time, better than 0.1%) once switched on, but the output reproducibility from one switch-on to the next or over long time periods is not as good (e.g. 0.5%). The reproducubility from one switch on to the next is sufficient to monitor the long-term detector stability and to study binning effects in the determination of bad and dead detector pixels. The corresponding dark (background) measurements of ICID 26 are available for background correction in case this would be required. The background correction is also performed in the 0-1 data processor. The LED measurements are stored in the level-1b calibration data product.