China Spallation Neutron Source (CSNS), the biggest platform for neutron scattering research in China, has been finished construction and already in user operation stage by the end of 2017. During the multi-turn charge-exchange injection, H⁻ stripping by a carbon primary stripper foil (100 ¿g/cm²) and a secondary stripper foil (200 ¿g/cm²) is adopted for this high intensity proton synchrotron. In order to evaluate the stripping efficiency and the foil aging, a dual-function low noise current transformer and corresponding electronics are designed to measure the ultra-low intensity of H⁻ and H⁰, which are not stripped completely by the 1st foil but totally stripped charge changing to H⁺ and delivered to the IN-DUMP. The self-designed CT sensors made of domestic nanocrystalline toroids, the noise analysis and elimination, measurement results and further improvement proposals are presented in this paper.
Proceedings of the 8th International Beam Instrumentation Conference, IBIC2019, Malmö, Sweden