An experimental measurement of the D-D fusion reaction cross-sections in the energy range of 70 to 250 keV is carried out at the neutron generator. A fusion reaction chamber with eight angles and a thin deuterated polystyrene target are used in the experiment. The passivated implanted planar silicon (PIPS) detectors are used to detect the products of charged-particle fusion reactions, and a high-precision digital electrometer is employed to measure the beam current from the target.

The differential cross-sections at six energies in the energy range are measured. The Legendre polynomials are used to fit the experimental differential cross-sections in the center-of-mass frame. According to the fitting results, the integral cross-sections at different energies are extracted. The differential and integral cross-sections at different energies are compared with historical experimental results and the evaluation data from the ENDF/B-VIII.0 database. Then, calculations of the astrophysical S(E) function are performed using the experimental integral cross-section data and compared with historical results. The results of this experiment further enrich the experimental data on D-D fusion reaction cross-sections, providing stronger data support for accurate calculation of the reaction rates in the standard Big Bang nucleosynthesis model and for the evaluation of fusion nuclear parameter data. The datasets presented in this paper, including a brief introduction to the experimental setup, the differential cross-section data, and the integral cross-section data, are openly available at https://www.doi.org/10.57760/sciencedb.j00213.00243.