Remeasurement of the $^{239}$Pu(n,f)/$^{235}$U(n,f) Cross-Section Ratio with the NIFFTE fission Time Projection Chamber Using Vapor-deposited Targets

D. H. Dongwi; L. Snyder; V. Aguilar; N. Androski; M. Anastasiou; N. S. Bowden; A. Chemey; T. Classen; J. E. Fuzaro Alencar; U. Greife; M. Haseman; L. D. Isenhower; J. L. Klay; W. Loveland; M. P. Mendenhall; M. Monterial; M. Silveira; C. Prokop; T. S. Watson; L. Yao

arXiv · 2409.18279

Remeasurement of the $^{239}$Pu(n,f)/$^{235}$U(n,f) Cross-Section Ratio with the NIFFTE fission Time Projection Chamber Using Vapor-deposited Targets

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Abstract

The NIFFTE fission Time Projection Chamber (fissionTPC) has been used to measure the $^{239}$Pu(n,f)/$^{235}$U(n,f) cross-section ratio for neutron-induced fission in the range of 0.1 - 100 MeV, with high precision. A white neutron source was provided by the Los Alamos Neutron Science Center, where the experiment was conducted as a remeasurement to evaluate a roughly 2% discrepancy of the previous fissionTPC results with ENDF/B-VIII.0. A detailed accounting of measurement uncertainties was performed, based on the fissionTPC's novel ability to provide three-dimensional reconstruction of fission-fragment ionization profiles. Current results obtained using a vapor-deposited, highly uniform $^{239}$Pu target, in comparison to the measurement published in 2021, where a $^{239}$Pu electroplated target was used, are presented and discussed. The remeasurement presented here is in agreement with the previous fissionTPC result within measurement uncertainties.

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D. H. Dongwi, L. Snyder, V. Aguilar, N. Androski, M. Anastasiou, N. S. Bowden, A. Chemey, T. Classen, J. E. Fuzaro Alencar, U. Greife, M. Haseman, L. D. Isenhower, J. L. Klay, W. Loveland, M. P. Mendenhall, M. Monterial, M. Silveira, C. Prokop, T. S. Watson, L. Yao. 2024-09-26. Remeasurement of the $^{239}$Pu(n,f)/$^{235}$U(n,f) Cross-Section Ratio with the NIFFTE fission Time Projection Chamber Using Vapor-deposited Targets. https://arxiv.org/abs/2409.18279

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