engleski

Compton Scattering study of the electron momentum density by using COLTRIM spectroscopy

Compton scattering of photons provides an important experimental method for studying electron momentum density (EMD) of electronic systems. With such a probe, and by interpreting experimental results within impulse approximation (IA), the information on EMD is obtained either from the measurements of spectrum of scattered photons (cross section integrated over ejected electrons which are not observed) or from the coincidence measurements of outgoing photon and ejected electron. At relatively high photon energies the IA gives that the spectrum is proportional to Compton profile which is a twofold integral over EMD. Much higher energies are needed to interpret coincidence measurements within IA, in which case IA gives that coincidence cross section is directly proportional to EMD. Recently it has been proposed to study EMD of an atomic system with Compton scattering by observing the momentum of recoiled ion (cross section is integrated over both outgoing photon and electron). In IA this cross section is proportional to EMD. Here we discuss the adequacy of IA for describing distribution of recoiled ions and for extracting information on EMD for different photon energies and recoiled ion angles. We present results for recoiled ion momentum distribution in Compton scattering from hydrogen atom (which can be treated exactly) and from He atom (for which experimental data obtained by COLTRIM spectroscopy exist).

Compton scattering; correlations; COLTRIM; electron momentum

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