STRUCTURE OF MASS DISTRIBUTIONS OF PHOTOFISSION PRODUCT YIELDS OF 238U AT 17.5 MeV BREMSSTRAHLUNG ENERGY

Abstract

The values of 29 relative yields of products belonging to 26 mass chains of photofission of 238U were obtained at a maximum bremsstrahlung energy of 17.5 MeV (near the second chance fission threshold). The stimulation of the 238U photofission reaction was performed at the electron accelerator of the Institute of Electron Physics of the National Academy of Sciences of Ukraine, the M-30 microtron. The GEANT4 toolkit was used to model the components of the bremsstrahlung spectrum. The presence of a fine structure in the mass distribution of heavy product yields was found to be localized in the mass range 133-134, 138-139, and 143-144. A multi gaussian model (superposition of three Gaussians) was used to theoretically describe the structure. The calculated values of product yields using the GEF code describe in general terms and predict the fine structure of the mass distribution of photofission products of 238U.