Optimization of Geomagnetic Shielding for MKIDs Mounted on a Rotating Cryostat
Optimization of Geomagnetic Shielding for MKIDs Mounted on a Rotating Cryostat
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安装在旋转低温恒温器上的 MKID 地磁屏蔽优化
DOI：
10.1007/s10909-018-2036-7
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发表时间：
2018
影响因子：
2
通讯作者：
Tajima Osamu
中科院分区：
文献类型：
--
作者：
Kutsuma Hiroki;Hattori Makoto;Kiuchi Kenji;Mima Satoru;Nagasaki Taketo;Oguri Shugo;Suzuki Junya;Tajima Osamu
超导探测器，如微波动态电感探测器（MKID），对周围磁场的影响很敏感。磁场对MKID的响应有两种影响：超导材料内部磁场的捕获降低了谐振器的质量，磁场的时间变化导致基线波动。在射电天文学的情况下，这意味着探测器必须受到地磁场的保护。在这里，我们构建了一个测试系统来评估所描述的效果。我们还评估了磁屏蔽的影响。我们发现，在噪声等效功率为的应用情况下，47 dB的屏蔽功率是必要的。我们还确认，使用坡莫合金薄膜获得的测量屏蔽功率与基于有限元法的模拟一致，精度为1 dB。我们已经设计了磁屏蔽的GroundBird CMB望远镜使用这些结果。我们实现了55 dB的足够屏蔽功率。
Superconducting detectors, such as microwave kinetic inductance detectors (MKIDs), are sensitive to the effects of ambient magnetic fields. There are two effects magnetic fields have on the response of MKIDs; the trapping of magnetic fields inside the superconducting materials degrades the resonator quality, and the time variation of the magnetic fields results in a baseline fluctuation. In the case of radio astronomy, this means the detector must be protected from the geomagnetic field. Here, we construct a test system to evaluate the effects described. We also evaluate the impact of the magnetic shield. We find that a shielding power of 47 dB is necessary in the case of application with a noise equivalent power of. We also confirm that the measured shielding power obtained using permalloy films is consistent with simulations based on the finite element method to an accuracy of 1 dB. We have designed magnetic shields for the GroundBIRD CMB telescope using these results. We achieve a sufficient shielding power of 55 dB.