CZTI Calibration

The CZT detectors are primarily designed as gamma-ray devices (40 - 200 keV) to be operated at room temperature. We are using them as X-ray spectroscopic detectors in the 10 - 100 keV regions. To extend the low energy response to 10 keV, the devices are cooled to 10ºC (+/- 5ºC) but in some orbits the temperature can go up to 20ºC. The X-ray spectroscopic capabilities are examined critically in the full energy range and the results are given in this report. CZTI uses a Coded Aperture Mask (CAM) as an imaging device. Calibration of the CAM is done separately. Similarly, the efficacy of alpha-tagging and CsI veto anti-coincidence are dealt with separately. All X-ray photons registered in CZTI are time tagged to an accuracy of 20 µsec. This provided an unexpected bonus of using CZTI as an X-ray polarization instrument above about 150 keV. This aspect of the calibration is discussed separately.

  • Evaluation of the dead, noisy, and bad pixels in CZTI
  • X-ray spectroscopic calibration at various temperatures
  • CAM Calibration
  • Alpha-tagging in CZTI
  • Veto calibration
  • Time tagging, cross talk and polarization capability of CZTI
  • Response matrix generation for CZTI
  • Testing at various modes
  • Calibration of the Integrated Flight Model