Multiple scattering double Compton model: determination of intrinsic efficiencies by calculating electron energies

ABSTRACT

For the measurement of the energy spectra generated by photons up to 320 keV (X-rays) that can be considered by the superposition of a set of monoenergetic photons, several types of detectors have been used, mainly Ge detectors. Each spectrum can be considered as the superposition of a beam of monoenergetic photons that contain a photoelectric peak, a Compton distribution, the characteristic radiation, and a multiple scattering region, which is located between the Compton edge and the photoelectric peak. In this article, a theoretical model is developed for finding the multiple scattering region. To this end, double Compton scattering is proposed, wherein the electron in motion after the first collision suffers a second Compton scattering by a photon going in the same direction. Using the theory of special relativity and the Lorentz invariants, the kinetic energy of the electron in motion is calculated. Then, with the obtained value and the new Klein–Nishina formula, the cross-section of the absorbed electrons is calculated as a function of its kinetic energy. The model fits correctly for the multiple scattering region from four sources with a conventional multichannel analyser and its associated electronics.

KEYWORDS:

• X Ray
• multiple scattering
• intrinsic efficiency
• germanium detectors

Acknowledgments

We thank the support from the Department of Radioactive Standard, Olga García Díaz, as well as Rubén Olivares López for the experimental development of this work. Finally, we thank Jos Tend´ılla del Pozo for his support for the publication of this article.

Disclosure statement

No potential conflict of interest was reported by the author(s).