LAUSR

Abstract For analyzing energy distribution of charge exchange atoms the ion energy sweeping technique is suggested as an alternative to the conventional multichannel Neutral Particle Analyzer (NPA) diagnostics. New electronics for application of the sweeping technique in the presence of mass separation (MS) electromagnet is described. The L/R time constant of the magnet is about 200 ms. Variation of current trough the magnet from zero to 0.3 A during 5 ms is required for energy-sweeping technique implementation in the ion energy range of 0−2 keV. The voltage applied to electrostatic part of NPA should be varied from zero to 500 V (measured energy is 4.5 times higher than the applied voltage). The dependence of the electrostatic voltage on the MS magnet current should correspond to the NPA calibration curve. The problem of simultaneous variation of the voltage at electrostatic part and current in MS magnet in accordance with NPA calibration is solved by means of developed electronics with the use of a STM32F100 microprocessor as a control unit. Square wave pulses of 310 V of variable duration are applied to generate MS magnet current. The IGBT bridge is used as a power unit of the MS magnet. The electrostatic voltage was formed by digital to analog convertor unit of STM32F100 microprocessor. The synchronized output of two control signals is produced by means of the direct memory access unit of the STM32F100 microprocessor.