Calibration of an electrostatic accelerator for single-event-effects tests

Electronic devices in space are susceptible to single-event effects (SEEs) induced by energetic particles. SEEs induced by low-energy protons and low linear energy transfer (LET) particles have become a serious concern as device sizes decrease. Electrostatic accelerators are well-suited to the study of device responses in the low-LET region due to their ability to provide a wide variety of ion species, a broad energy range, and precise energy control. It is essential to precisely control the incident ion beam energy and intensity when evaluating SEE cross-sections in the low-LET region. SEE tests require beam fluxes down to 10 2 particles/cm 2 /s, below the detection limit of conventional Faraday cups. We developed a beam current monitor and energy calibration techniques for SEE testing using a 1 MV electrostatic tandem accelerator. The beam monitor combined with a ZnS(Ag) scintillator was calibrated using a Faraday cup and a passivated implanted planar silicon (PIPS) detector. The dynamic range is 10 2 –10 9 particles/cm 2 /s, and the accuracy is ±30 %. Beam energy calibration was first performed by adjusting the terminal voltage using nuclear reaction methods. Subsequently, beam irradiation into the PIPS detector allowed direct measurement of beam energy. The measured energies were in good agreement with those obtained from a PIPS detector calibrated using an Am-241 source, confirming the validity of the direct calibration approach. We thus offer a stable experimental platform for low-LET SEE studies, expanding the applications of electrostatic accelerators that test space electronic devices.