Evaluation of T+t Reaction Cross Sections Based on R-matrix Theory

The present dataset was generated using the RAC program. The RAC program, developed by Professor Chen Zhenpeng at Tsinghua University and collaborators, is an R-matrix analysis code based on the generalized reduced R-matrix theory combined with covariance analysis. The code features a high degree of automation in adjusting R-matrix parameters, enables efficient fitting of large experimental datasets, and is well suited for the analysis of compound nuclear systems. By phenomenologically adjusting R-matrix parameters against experimental data, the program provides evaluated cross sections for all reaction channels defined within a given compound system.In this work, the RAC program was employed to evaluate the 6He compound nuclear system corresponding to the TT reaction. Experimental data related to the 6He system were collected from the EXFOR database and relevant literature, with emphasis placed on the cross sections of the T(t,2n)4He reaction. Preliminary evaluation results for multiple channels of the 6He system have been obtained. This dataset provides both integral and differential cross sections for the 6He system. The integral cross sections include T(t,2n)4He, T(t,n)5He, and T(t,d)4H, while the differential cross sections include T(t,2n)4He, T(t,n)5He, T(t,d)4H, and T(t,t)T. The evaluated results are primarily compared with available experimental data and the latest evaluated data from ENDF/B-VIII.1. The dataset consists of 15 files in total, detailed as follows:1. T(t,2n)4He-CS: Evaluated integral cross sections of T(t,2n)4He including RAC-2025, ENDF/B-VIII.1, TENDL-2023, and experimental data (CSV format, viewable with any text editor).2. T(t,n)5He-CS: Evaluated integral cross sections of T(t,n)5He, including RAC-2025 and experimental data (CSV format, viewable with any text editor).3. T(t,d)4H-CS: Evaluated integral cross sections of T(t,d)4H, including RAC-2025 and experimental data (CSV format, viewable with any text editor).4. T(t,2n)4He-4He-DA-0deg: Excitation function of 4He emitted at 0° (laboratory frame) from the T(t,2n)4He reaction, including RAC-2025 and experimental data (CSV format, viewable with any text editor).5. T(t,2n)4He-4He-DA-30deg: Excitation function of 4He emitted at 30° from the T(t,2n)4He reaction (CSV format, viewable with any text editor).6. T(t,2n)4He-4He-DA-90deg: Excitation function of 4He emitted at 90° from the T(t,2n)4He reaction (CSV format, viewable with any text editor).7. T(t,2n)4He-4He-DA-1.9MeV: Angular distribution of 4He at 1.9 MeV incident energy for the T(t,2n)4He reaction (CSV format, viewable with any text editor).8. T(t,n)5He-n-DA-5.98MeV: Angular distribution of neutrons at 5.98 MeV for the T(t,n)5He reaction (CSV format, viewable with any text editor).9. T(t,n)5He-n-DA-10.45MeV: Angular distribution of neutrons at 10.45 MeV for the T(t,n)5He reaction (CSV format, viewable with any text editor).10. T(t,n)5He-n-DA-16.41MeV: Angular distribution of neutrons at 16.41 MeV for the T(t,n)5He reaction (CSV format, viewable with any text editor).11. T(t,n)5He-n-DA-19.14MeV: Angular distribution of neutrons at 19.14 MeV for the T(t,n)5He reaction (CSV format, viewable with any text editor).12. T(t,d)4H-d-DA-16.41MeV: Angular distribution of deuterons at 16.41 MeV for the T(t,d)4H reaction (CSV format, viewable with any text editor).13. T(t,d)4H-d-DA-19.14MeV: Angular distribution of deuterons at 19.14 MeV for the T(t,d)4H reaction (CSV format, viewable with any text editor).14. T(t,t)T-t-DA-1.582MeV: Angular distribution of tritons at 1.582 MeV for the T(t,t)T reaction (CSV format, viewable with any text editor).15. T(t,t)T-t-DA-1.8MeV: Angular distribution of tritons at 1.8 MeV for the T(t,t)T reaction (CSV format, viewable with any text editor).According to current investigations, no systematic evaluation of the 6He system corresponding to the TT reaction has yet been carried out domestically, and this dataset to some extent fills the gap in national evaluations of TT reaction cross sections. In comparison with international evaluations, it also provides preliminary results for certain channels, such as the integral and differential cross sections of the T(t,n)5He reaction, which are not included in ENDF/B-VIII.1. It is expected that this dataset will serve as a useful reference for both domestic and international researchers studying the 6He system.