A Quick and Sensitive Method of Measuring the Proportion of High-harmonic Components for Synchrotron Radiation using Ionization Chambers

The proportion of high-harmonic components included in monochromatized synchrotron radiation was measured with a combination of two free-air ionization chambers. The absolute intensity of the fundamental photons was measured with a chamber having a narrow gap. For the high harmonics, the intensity attenuated through a foil set to remove the fundamental component, was measured with a chamber having a wide gap and converted to the intensity before the foil considering the attenuation. The measurement result was compared with that of an Hp-Ge detector, and close agreement was obtained. Several advantages of this method over the spectrum measurement method were confirmed in the present experiment: namely, a short measuring time, adequate sensitivity even to low high-harmonic proportions and availability at low energies