Oxidation Yield of the Ferrous Ion in a Fricke Solution Irradiated with Monochromatic Synchrotron Soft X-rays in the 1·8–10 KeV Region

The oxidation yield of ferrous ion in a Fricke solution was measured in the soft X-ray region from 1.8 to 10 keV. The standard Fricke solution was irradiated with monochromatic X-rays from synchrotron radiation. The yield decreased with decreasing X-ray energy, as several theoretical calculations have predicted. No significant changes were observed in the K-shell photo-absorption of the iron and sulphur contained in the standard Fricke solution. The high-LET nature of soft X-rays is discussed.