Background <p>With the recent advancements in accelerator mass spectrometry (AMS) technology, particularly in terms of compactness and low-energy capabilities, the accurate measurement of low-energy ions below 200&#xa0;keV has become a crucial area of research.</p> Method <p>A novel single-anode gas ionization chamber (GIC) has been developed for low-energy ion counting in AMS. This innovative GIC consists of a 50-nm silicon nitride window, an anode, a Frisch grid, and a cathode. To optimize the measurement conditions and evaluate the detector's performance at low energies, test experiments were conducted using a ²³⁹Pu/²⁴¹Am α source and ³H and ¹⁴C ions at the energies of ~ 180 keV.</p> Results <p>The experiments showed that the energy resolutions of α particles produced by ²³⁹Pu and ²⁴¹Am decay were approximately 5%. For the testing of ³H and ¹⁴C ions at around 180 keV using the gas detector, the results indicate that the electronic noise is effectively distinguished from the low-energy ions that require measurement.</p> Conclusion <p>The new designed of GIC is specifically tailored for measuring ions at low energy, making it compliant with the stringent requirements for low-energy ion measurements at GXNU-AMS.</p>