Krause C, Drung D, Götz M, Scherer H
Physikalisch-Technische Bundesanstalt (PTB), Abbestraße 2-12, 10587 Berlin, Germany.
Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany.
Rev Sci Instrum. 2019 Jan;90(1):014706. doi: 10.1063/1.5078572.
We have developed a noise-optimized ultrastable low-noise current amplifier (ULCA) aimed at reducing the uncertainty at low currents. It involves a thin-film resistor network with 6.75 GΩ at the high-ohmic path which reduces the noise level to 1.6 fA/Hz. Noise investigations as well as short-term and long-term stability studies were carried out. The stability of the input current gain was measured using a cryogenic current comparator at ±6.1 nA. Methods for investigating the measurement accuracy at low input currents of about 100 pA at a level of below one part in 10 are introduced and experimentally verified. The performance of the noise-optimized ULCA is compared with that of the standard variant introduced in 2014. It is shown that the reduced noise floor is achieved without impairing the stability of the transresistance.
我们开发了一种经过噪声优化的超稳定低噪声电流放大器（ULCA），旨在降低低电流时的不确定性。它包括一个在高电阻路径上具有6.75 GΩ的薄膜电阻网络，可将噪声水平降低至1.6 fA/Hz。进行了噪声研究以及短期和长期稳定性研究。使用低温电流比较器在±6.1 nA下测量输入电流增益的稳定性。介绍并通过实验验证了在低于十分之一的水平下研究约100 pA低输入电流时测量精度的方法。将经过噪声优化的ULCA的性能与2014年推出的标准变体进行了比较。结果表明，在不损害跨阻稳定性的情况下实现了更低的本底噪声。
