Reasons why Plutonium 242 is the best fission chamber deposit to monitor the fast component of a high neutron flux

Philippe Filliatre, Ludovic Oriol, Christian Jammes, Ludo Vermeeren, Marcel Wéber

    Research outputpeer-review


    The FNDS project aims at developing fission chambers to measure on-line the fast component of a high neutron flux (≈1014 ncm-2s-1 or more) with a significant thermal component. We identify with simulations the deposits of fission chambers that are best suited to this goal. We address the question of the evolution of the deposit by radiative capture and decay. A deposit of 242Pu appears as the best choice, with a high initial sensitivity to fast neutrons only slowly degrading under irradiation. The effect of unavoidable impurities was assessed: small concentrations of 241Pu and 243Pu can be tolerated.

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