A successful experimental observation of double-photon Compton scattering of γ rays using a single γ detector

The phenomenon of double-photon Compton scattering has been successfully observed using a single gamma detector, a technique avoiding the use of the complicated slow-fast coincidence set-up used till now for observing this higher-order process. Here doubly differential collision cross-sections integrated over the directions of one of the two final photons, the direction of other one being kept fixed, are measured experimentally for 0.662 MeV incident gamma photons. The energy spectra of the detected photons are observed as a long tail to the single-photon Compton line on the lower side of the full energy peak in the recorded scattered energy spectrum. The present results are in agreement with theory of this process. (C) 2005 Elsevier Ltd. All rights reserved.