Measurement of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi mathvariant="normal">Am</mml:mi><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>241</mml:mn></mml:mrow></mml:mmultiscripts></mml:math>(<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>n</mml:mi><mml:mo>,</mml:mo><mml:mn>2</mml:mn><mml:mi>n</mml:mi></mml:mrow></mml:math>) reaction cross section from 7.6 MeV to 14.5 MeV

The ($n,2n$) cross section of the radioactive isotope $^{241}\mathrm{Am}$ (${T}_{1/2}=432.6$ y) has been measured in the incident neutron energy range from 7.6 to 14.5 MeV in steps of a few MeV using the activation technique. Monoenergetic neutron beams were produced via the $^{2}\mathrm{H}$($d,n$)$^{3}\mathrm{He}$ reaction by bombarding a pressurized deuterium gas cell with an energetic deuteron beam at the TUNL 10-MV Van de Graaff accelerator facility. The induced \ensuremath{\gamma}-ray activity of $^{240}\mathrm{Am}$ was measured with high-resolution HPGe detectors. The cross section was determined relative to Al, Ni, and Au neutron activation monitor foils, measured in the same geometry. Good agreement is obtained with previous measurements at around 9 and 14 MeV, whereas for a large discrepancy is observed when our data are compared to those reported by Perdikakis et al. near 11 MeV. Very good agreement is found with the END-B/VII evaluation, whereas the JENDL-3.3 evaluation is in fair agreement with our data.