Accurate fission cross-sectional data for actinide nuclides are critical for nuclear energy, astrophysics, and defense applications. Traditional detectors, such as fission chambers, face limitations in achieving sub-3% uncertainty owing to particle identification challenges and dynamic range constraints. The time projection chamber (TPC) can record both the energy deposition \(\textrm{d}E/\textrm{d}x\) and the three-dimensional track of an event, providing the ability to identify particles and fission fragments. Based on this characteristic, we developed a novel TPC, INPC-TPC, featuring a symmetrical dual-chamber structure and gas electron multiplier (GEM)-based readout technology. The dual-chamber design isolates fission fragments and recoils protons, thereby reducing the dynamic range requirements of a single chamber, whereas the GEM ensures high spatial resolution and stable gain. Experiments conducted at the Chinese Spallation Neutron Source (CSNS) Back-n white neutron beamline validated the performance of the proposed detector. The INPC-TPC demonstrated effective fission fragment identification through particle energy-length correlation measurements and accurately measured the neutron beam spot size with a diameter relative error of < 2%. The results highlight the capability of the system to achieve high-precision measurements of neutron-induced fission cross sections, particularly for 235U and 238U.
