General formalism for calculating gamma-ray buildup factors in multilayer shields into MERCURE-6 code

This study proposes a new method for calculating gamma-ray buildup factors in multilayer shields. The formula combines the buildup of single-layer shields with products and quotients. The tests have shown that the approximating formula reproduces the reference data of double layer shields very well for most cases. With the same parameters and with a new physical consideration that takes into account in a global way the degradation of the gamma-ray energy spectrum, the buildup factors of three and five layer shields were also very well reproduced. The new formula is incorporated in the new version of the MERCURE-6 point-kernel code. (author)