分类: 核科学技术 >> 辐射物理与技术 提交时间: 2024-07-28
摘要: Stripping unit plays an important role in the neutral particle analyzer (NPA). An updated gas stripping unit was constructed for the newly designed E//B NPA. The pressures at the gas inlet ($P_0$) and the vacuum chamber ($P_3$) were measured with the working gas of H$_2$, and the pressure distribution inside the gas stripping room was calculated using Ansys Fluent with the measured $P_0$ and $P_3$ as the boundary conditions. The stripping efficiency of the stripping unit is then simulated using Geant4 Monte Carlo code for H and D particles. The pressure $P_0$ = 40 Pa, which is four times less than that in previous design and corresponds to a thickness of 1.27$\times 10^{17}$ atoms/cm$^2$, is obtained as the optimum working pressure for the updated stripping unit.A 50 kV electron cyclotron resonance (ECR) ion source platform has been designed and constructed for the E//B NPA calibration, and its performance was measured. Utilizing the ECR ion source platform, the efficiency of the stripping unit was measured in an inverse experiment with proton beams. The current ratio of the measurements with and without H$_2$ gas are compared with those of Geant4 simulation. Good agreements of the overall trend between the experiment and the simulation are found. The large deviation at the incident energy below 20 keV could be the scattering effect of low energy protons, where the accuracy breaks down in the single scattering physics involved in the Geant4 simulations. {After the scattering corrections observed in the reverse experiments, more accurate stripping efficiencies for H and D atoms in the energy range of 20-200 keV are obtained and the global efficiency reaches the maximum values of 95.0\% for H atoms and 78.9\% for D atoms at 200 keV.