It introduces a circuit design of beam homogeneity measurement for heavy ion beam in the monitoring needs, which convert multichannel weak current from 10 pA to 100 nA of the output of parallel plate avalanche counter( PPAC) for large area with sensitive two - dimensional position to voltage signal from -2 V to -20 mV by current - voltage - convertor(IVC) circuit which composed of T - feedback resistor networks, combined with data acquisition and processing system realized the beam homogeneity measurement in heavy ion tumor therapy of the Institute of Modern Physics. Experiments have shown that the circuit with speed and high precision, This circuit can be used for read -out of the beam for the Multiwire Proportional Chamber, Faraday Cup and other weak current sources.%针对重离子治癌中的束流监测需要,用T型反馈电阻网络组成的电流-电压转换(IVC)电路将大面积二维位置灵敏平行板雪崩探测器( PPAC)输出的多路10pA～100 nA的微弱电流转换成-2V～-20 mV的电压信号,配合数据获取处理系统实现了近代物理研究所重离子治癌中的束流均匀性测量.实验表明该电路具有速度快、精度高等优点,该电路也可用于法拉第筒及多丝正比室的束流读出.
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