Design of Pickup Coil Made of Litz Wire and Cooled at 77 K for High Sensitive Measurement of AC Magnetic Fields
Design of Pickup Coil Made of Litz Wire and Cooled at 77 K for High Sensitive Measurement of AC Magnetic Fields
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DOI：
10.1143/jjap.50.076602
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发表时间：
2011-07-01
影响因子：
1.5
通讯作者：
Kandori, Akihiko
中科院分区：
文献类型：
--
作者：
Enpuku, Keiji;Hirakawa, Shintaro;Kandori, Akihiko
我们研究了用于交流磁场高灵敏度测量的铜拾取线圈的性能。线圈采用Litz丝制成，以防止集肤效应，并在77 K下冷却，以减少热噪声。首先通过对线圈涡流损耗的分析，得到了线圈电阻的解析表达式。分析结果很好地解释了线圈电阻对频率、线圈匝数(N)和Litz丝丝直径（d(f)）的测量依赖性。接下来，我们将展示拾音器线圈的设计。当为N和df选择适当的值时，我们可以预期磁场噪声S(B)(1/2) < 10 fT/Hz(1/2)，对于直径为50 mm的拾取线圈，f >为10 kHz时，S(B)(1/2) < 2 fT/Hz（1/2）。试验结果与设计值基本一致。(C) 2011 .日本应用物理学会
We studied the performance of a copper pickup coil for high sensitive measurements of ac magnetic fields. The coil was made of Litz wire to prevent the skin effect, and was cooled at 77 K to reduce thermal noise. We first obtained an analytical expression for the coil resistance by analyzing the eddy current loss of the coil. The analytical result explains well the measured dependences of the coil resistance on the frequency, number of turns of the coil (N), and filament diameter of the Litz wire (d(f)). Next, we show the design of the pickup coil. When appropriate values are selected for N and df, we can expect the magnetic field noise S(B)(1/2) < 10 fT/Hz(1/2) for f > 1 kHz and S(B)(1/2) < 2 fT/Hz(1/2) for f > 10 kHz for the pickup coil with diameter of 50 mm. The experimental results agreed with the designed values. (C) 2011 The Japan Society of Applied Physics