摘要
本文介绍一台低噪声FET放大器的设计及特性,它用于de-SQUID信号检测,同时分析了放大器输入端信号传输线对输入噪声电流的影响。在SQUID调制频率50kHz条件下,利用双绞漆包线作为输入信号线的放大器噪声电压为0.48nV/Hz^(1/2),噪声电流为79.2fA/Hz^(1/2).放大器增益66dB,3dB带宽为15kHz～150kHz.该放大器已用于PIC-1型dc-SQUID超导磁强计中,频率1Hz时的磁通噪声(rms值)为1×10^(-4)φ_(orms)Hz^(1/2).
The design and performance of a low-noise FET amplifier , which is used as preamplifier to detect the dc-SQUID signal in the superconducting magnetometer, is described. The influence of transmission line connecting the dc SQUID probe to the preamplifier on the input current noise is analyzed. Using twisted enamel-insylated wire pair as transmission line, the voltage noise of the preamplifier is 0-48nV Hz , the current noise is 79-2fA Hz, at the dc-SQUID modulation frequency of 50 KHz. The gain is 66 dB, and the 3 dB bandwidth is from 15KHz to 150 KHz.
出处
《低温与超导》
CAS
CSCD
北大核心
1992年第4期45-50,共6页
Cryogenics and Superconductivity
