Novel, Non‐contact Noise Thermometer for Milli‐kelvin Temperatures
Novel, Non‐contact Noise Thermometer for Milli‐kelvin Temperatures
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适用于毫开尔文温度的新型非接触式噪声温度计
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
A. Fleischmann
中科院分区：
文献类型：
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作者：
A. Netsch;E. Hassinger;C. Enss;A. Fleischmann
电阻器的热驱动电压波动的温度依赖性由耗散波动定理描述。统计物理学的这一基本定律提供了温度和独立可测量量之间的直接关系，使得噪声测量成为在宽温度范围内进行初级测温的有吸引力的选择。然而，实现这种温度计用于测量非常低的温度通常是有问题的，这阻止了该技术在低温实验室中的广泛使用。我们提出了一种新的约翰逊噪声测温的非接触式方法，它使用商业dc-SQUID作为探测器。要测量的噪声是由高纯度金属（如金或铜）的大块样品中电子的热运动产生的。这些随机电流导致连接到电流传感器SQUID输入线圈的拾取线圈中的磁通量波动。该温度计易于制作。
The temperature dependence of thermally driven voltage fluctuations of an electrical resistor is described by the dissipation‐fluctuation theorem. This fundamental law of statistical physics provides a direct relation between temperature and independently measurable quantities, making the measurement of noise an attractive option for primary thermometry in a wide range of temperatures. However, the realization of such thermometers for the measurement of very low temperatures has often been problematic, preventing this technique from being widely used in low temperature laboratories. We present a novel non‐contact approach for Johnson‐noise thermometry which uses a commercial dc‐SQUID as preamplifier. The noise to be measured is generated by the thermal motion of electrons in a bulk sample of a high purity metal such as gold or copper. These random currents cause fluctuations of magnetic flux in a pickup coil which is connected to the input coil of a current‐sensor SQUID. The thermometer is easy to fabrica...