Femtoampere current reference stable over atmospheric temperatures
Femtoampere current reference stable over atmospheric temperatures
复制标题
飞安电流基准在大气温度范围内保持稳定
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
K. Aplin
中科院分区：
文献类型：
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作者：
R. Harrison;K. Aplin
校准部署在大气离子计数器中的超小电流安培计需要在高源阻抗下工作的稳定电流基准。该基准电流源使用标准精密元件，可产生标称为±500 fA的相等双极电流，每个电流周期为32 S。在−20到20 °C的温度范围内，电流被发现稳定在2 fA，这是典型的大气条件。输出电流通过电容器提供，当系统不产生电流时，通过安排将电容器保护在地电位，基准可以永久地连接到静电计，泄漏最小。
Calibration of ultralow current ammeters deployed in atmospheric ion counters requires stable current references operating at high source impedance. Using standard precision components, this current reference generates equal bipolar currents of nominally ±500 fA, cyclically for 32 s each. The currents were found to be stable to 2 fA over the temperature range −20 to 20 °C, typical of atmospheric conditions. The output current is delivered via a capacitor, and by arranging for the capacitor to be guarded at ground potential when the system is not generating a current, the reference can be permanently connected to an electrometer with minimal leakage.