engleski

Experimental determination of absolute-scale Compton cross sections using the K X-ray escape and a comparison with three versions of the impulse approximation

Double-differential Compton cross sections at two incident photon energies of 68.9 and 70.8 keV (mercury Kalpha X-rays) at the scattering angle of about 172 degrees were measured in germanium using the coincidence technique with a detector as a scatterer. The cross sections were determined by normalization of the Compton spectra to the peaks due to the escape of characteristic Kalpha and Kbeta X-rays from the target detector. This new approach in determination of absolute-scale of the Compton cross section can also be applied in the widely-used single-mode measurements (source-scatterer-detector assembly). Our analysis shows that the new method is especially convenient and accurate at lower incident photon energies above the K-edge in the target atoms. The experimental results are compared with the non-relativistic impulse approximation, the frequently used simplified version of the relativistic impulse approximation and the non-relativistic impulse approximation used with the relativistic expression for the atomic electron momentum in the direction of the photon momentum transfer. Contrary to our expectation, the non-relativistic impulse approximation clearly gives the best agreement with the experimental data in the region of the Compton peak.

impulse approximation; Compton scattering; Compton cross section; absolute-scale measurement

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