DEVELOPMENT OF AN (X,EX) SPECTROMETER FOR MEASURING THE ENERGIES OF THE SCATTERED PHOTON AND RECOIL ELECTRON

The design and performance of a new spectrometer for coincidence measu rements between the Compton scattered photon and the recoil electron a re described. Coincidence measurements give direct information on the three-dimensional electron momentum density (EMD) of condensed matter. The present spectrometer measures energy spectra of both the photon a nd the electron. The energy spectrum of electrons is measured by a tim e-of-flight method using single-bunch operation at the Photon Factory Accumulator Ring (PF-AR). The energy resolution obtained for the recoi l electron is 190 eV, which is better than that of the photon detector , so that a momentum resolution of the three-dimensional EMD of 0.3 at omic units can be achieved.