Calibration Of X Ray Ion Chambers For The Space Environment Monitoring System

Calibration of X-ray Ion Chambers for the Space Environment Monitoring System

Measurements of the steady-state of the ion-chamber current output to the incident energy flux of a monochromatic X-ray beam are reported for the 1/2-3 Å and 1-8 Å ion chambers for the NOAA Space Environment Monitoring System. Bragg crystal reflection was employed to obtain a monochromatic beam. Proportional counters were used to measure the absolute intensity of the monochromatic X-ray beam. An ultra-sensitive electrometer was used to measure the current output of the ion chamber, including currents as small as 10−15 amps with noise levels as low as about 10−16 amps. The calibration results are compared with the theoretical transfer function. The effects of anode structures on reducing the effective total area of the ion chambers were observed as a function of wavelength. The influence of small regions of epoxy overlying the window was examined.

NOAA Technical Report ERL.

NOAA Technical Report ERL.