Spectra of Bremsstrahlung Produced in Very Thick Lead Targets by 15-, 20-, and 25-MeV Electrons

Abstract

The spectra of bremsstrahlung from very thick lead targets bombarded by 15-, 20-, and 25-MeV electrons from a linear accelerator were measured with activation detectors. This activation method has the advantage of being available for measuring the spectrum of a bremsstrahlung burst and being suitable for determining the distribution of the photon energy spectrum in the medium. By use of the most accurate photonuclear cross section data available, the bremsstrahlung spectra were evaluated with the LYRA unfolding code. The evaluated spectra were in good agreement with the calculated spectra, especially at 9 deg for 15- and 20-MeV electrons. It is concluded that the spectrometry of bremsstrahlung radiation by activation detectors can satisfactorily represent the variation of bremsstrahlung spectrum as a function of incident electron energy. The spectra obtained by this method are very much dependent on the photonuclear cross section data of activation detectors. This activation experiment can be used as an integral experiment to evaluate photonuclear cross section data by coupling with the reference calculations. 4 tables, 7 figures. (auth)