Development of a Low-noise, Single-stage Pulse-tube Cryocooler
Development of a Low-noise, Single-stage Pulse-tube Cryocooler
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低噪声单级脉冲管制冷机的开发
DOI：
10.2221/jcsj.39.322
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
T. Nagaishi
中科院分区：
文献类型：
--
作者：
S. Fujimoto;Y. Hiratsuka;H. Morishita;T. Nagaishi
研制了一种低噪声脉冲管制冷机。它适用于冷却可变半导体或超导器件。该制冷机的电磁噪声和倾斜特性得到了改善，在77 K、输入功率为800 W时制冷量为4.9W。最低温度低于49 K。在77 K的冷却性能是在5%的退化为所有的方向。低噪声脉冲管制冷机安装在一个低温恒温器设计的高Tc SQUID传感器。电磁噪声的测量是通过在低温恒温器中冷却的磁强计型SQUID传感器进行的。噪声水平受传感器方向的影响。当传感器平行于制冷机气缸时，检测到的白色噪声约为300 fT/kHz，没有观察到制冷机磁性材料或机械振动产生的循环噪声。当传感器垂直于圆柱体时，白色噪声约为2 pT/kHz，循环噪声约为10 pT rms。利用脉冲管制冷机制冷的高温超导量子干涉仪磁强计成功地进行了实时心磁图测量。信噪比优于传统的低温制冷系统。
A low-noise, pulse-tube cryocooler has been developed. It is suitable for cooling variable semiconductor or superconducting devices. The cryocooler's electro-magnetic noise and inclination characteristics are improved, and the cooling capacity is 4.9 W at 77 K with an input power of 800 W. The minimum temperature was less than 49 K. The cooling performance at 77 K was within 5% degradation for all orientations. The low-noise pulse-tube cryocooler was installed in a cryostat designed for a high-Tc SQUID sensor. The electro-magnetic noise was measured by the magnetometer-type SQUID sensor cooled in the cryostat. The noise level was influenced by the direction of the sensor. When the sensor was parallel to the cryocooler cylinder, the white noise was about 300 fT/√Hz and the cyclic noise produced by the cryocooler's magnetic material or mechanical vibration was not observed. When the sensor was vertical to the cylinder, the white noise was about 2 pT/√Hz and the cyclic noise was about 10 pT rms. A real-time magnetocardiography was successfully measured using a high-Tc SQUID magnetometer cooled by the pulse-tube cryocooler. The signal-to-noise ratio was better than the conventional cryocooling system.