Development of a high current Faraday Cup for JUNA experiments

[Background] Precise current measurement in accelerators is essential for nuclear astrophysics research. Precise absolute current measurement is required for the high-intensity accelerator of the Jinping Underground Laboratory for Nuclear Astrophysics (JUNA). [Purpose] This study aims to develop a high-power Faraday cup for the precise measurement of beam current in a 4 kW accelerator.. [Methods] The effect of secondary electron suppression was simulated using SIMION software, and an effective secondary electron suppression structure was designed and experimentally verified on a medical heavy ion accelerator for secondary electron suppression. The heat dissipation and cooling of the collection cup were also analyzed and calculated. The finite element analysis software COMSOL was used to perform the thermal-structural coupling analysis.. [Results] The results show that the secondary electrons are effectively suppressed when the negative bias voltage exceeds 200V. The newly designed suppression ring structure significantly improves the measurement accuracy of the Faraday cup. The thermal analysis simulation results are in accordance with the theoretical calculations, and the water-cooled Faraday cup can meet the requirements of the accelerator. [Conclusions] The Faraday cup has been successfully applied to the first high-intensity accelerator for deep earth experiments in China, and has shown stable and reliable performance, fully meeting the operational and experimental requirements of JUNA.