For the ionization radiation detectors, the output current of current ionization chamber is very weak and the current range is wide, proposed the use of direct current digital chip DDC112,to realize the dual channel continuous measurement of fA (10-15A) current. By one single -chip, charge signal is directly converted into 20 - bit digital output data, which simplify electronic circuit design, suppress the interference noise, improve the resolution, combining circuit anti - leakage current design process, achieve the system of high - performance ionization chamber measurement micro - current. After the actual circuit design and test, integration time can be adjusted in the range of 50 ～ 1×106μs, current range can be set up in the range of 5 ×104 ～ 7× 109fA by setting the integral time.%针对电离辐射探测器中电流电离室输出电流微弱,且电流范围较宽等特点,提出利用直接电流数字化集成芯片DDC112,实现双通道fA(飞安,10-15A)级微弱电流的连续测量.利用单芯片将电荷信号直接转化为20位数字输出,简化电子电路设计,降低干扰噪声,提高分辨率,配合电路防泄漏电流设计工艺,实现高性能电离室微电流测量系统.经过实际电路设计和调试,积分时间可在50～1×106μs范围内控制调整,电流量程可在5×104～7×109fA范围内根据积分时间进行选择.
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