X-ray attenuation/absorption data are from the NIST database.
The average ionization enegies are obtained from the SLAC web site.
Standard CHESS chamber lengths: short: 6 cm, long: 27 cm.
A calculator program uses a simple model to calculate the X-ray flux from the ion chamber current data. The model includes single-ionization of the gas, and does not takes into account some of the secondary effects such as charge recombination, or space-charge effect.
At station A2 with multi-layer optics at 10keV. The 6cm N2 ion chamber count was 109400 at 1E-6 gain. The calculated flux: 9.6E11 ph/s.
At station A2 with <111> optics at 50keV. The 6cm N2 ion chamber count was 722000 at 1E-10 gain. The calculated flux: 2.55E9 ph/s.