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Description
Accelerator based neutron sources generate a large number of secondary electrons during operation. For example, secondary electrons generated by cyclotrons will change the spatial distribution of the beam and reduce the stability of the beam. Secondary electrons generated by neutron generators will flow back to the ion source, increase the load of the high-voltage power supply, and affect the safety and stability of the equipment. For neutron generators, this paper uses numerical simulation methods to study the impact of different electric field parameters on secondary electron suppression. The results indicate that when the target voltage is fixed at 120 kV and the bias voltage changes from 600 V to 900 V, the target current decreases from 41.6 mA to 30 mA, indicating that the secondary electrons are completely suppressed. Meanwhile, when the bias voltage is set to 600 V, the target current increased from 30 mA to 41.5 mA as the target voltage was raised. Additionally, a greater inclination angle of the acceleration electrode and a closer baffle to the target can be also effective for the suppression of secondary electrons, the target current decreased from 41.6 mA to 38.2 mA when the inclination angle increased from 84º to 96º, furthermore, the lowest target current could be obtained at the inner baffle distance of 20 mm. This work provides theoretical guidance for the optimization of accelerator neutron sources.
