Americium-241 integral radiative capture cross section in over-moderated neutron spectrum from pile oscillator measurements in the Minerve reactor

Abstract

Abstract. An experimental program, called AMSTRAMGRAM, was recently conducted in the Minerve low power reactor operated by CEA Cadarache within the frame of the CHANDA initiative (Solving CHAllenges in Nuclear Data). Its aim was to measure the integral capture cross section of 241 Am in the thermal domain. Motivation of this work is driven by large differences in this actinide thermal point reported by major nuclear data libraries. The AMSTRAMGRAM experiment, that made use of well characterized EC-JRC americium samples, was based on the oscillation technique commonly implemented in the Minerve reactor. First results are presented and discussed in this article. A preliminary calculation scheme was used to compare measured and calculated results. It is shown that this work confirms a bias previously observed with JEFF-3.1.1 (C/E-1 = −10.5 ± 2%). On the opposite, the experiment is in close agreement with 241 Am thermal point reported in JEFF-3.2 (C/E-1 = 0.5 ± 2%).

Measurement and analysis of theAm241neutron capture cross section at the n_TOF facility at CERN

“…9). The conclusions that can be drawn are the following: [72] seems to confirm the value from JEFF-3.2. There is also a recent work which reviews previous thermal cross section measurements [73], and gives the value of 720(14) b.…”