Planar Lithographed Superconducting LC Resonators for Frequency-Domain Multiplexed Readout Systems
Planar Lithographed Superconducting LC Resonators for Frequency-Domain Multiplexed Readout Systems
复制标题
用于频域复用读出系统的平面光刻超导 LC 谐振器
DOI：
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
C. Tran
中科院分区：
文献类型：
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作者：
K. Rotermund;B. Barch;S. Chapman;K. Hattori;A. Lee;N. Palaio;I. Shirley;A. Suzuki;C. Tran
宇宙微波背景（CMB）偏振实验增加了跃迁边缘传感器（TES）测辐射热计的数量，以提高灵敏度。为了保持亚开尔文级的低热负载，频域复用（FDM）因子必须相应地增加。FDM是通过将TES测辐射热计与电感电容（LC）谐振器串联来实现的，电感电容谐振器选择读出频率。在总读出带宽大、通道间频率间隔小的情况下，可以提高复用因子。电感保持恒定，以保持整个探测器的均匀读出带宽，而最大可接受值由测辐射热计稳定性决定。目前的技术依赖于市售的陶瓷芯片电容器。这些在它们的电容中具有高散射，从而需要大的频率间隔。此外，它们在较高频率下具有高等效串联电阻（ESR），并且通过焊接进行手工组装耗时且繁琐。一种解决方案在于光刻的平面螺旋电感器（目前在一些实验中使用）与硅（Si）衬底上的叉指电容器组合。为了保持合理的器件尺寸，我们已经减少了LC的迹线和间隙宽度为4 $$\upmu $$μm。我们将电感从16 μH增加到60 μH，以实现更高的封装密度，这是具有大复用因子的FDM系统的要求。此外，Si衬底在整个频率范围内产生低ESR值，并且光刻使得LC对的大规模生产成为可能。我们通过将电感器与电容器放置在棋盘图案中来减少电感器之间的互感，从而增加相邻电感器之间的物理距离。我们还减少了电感器与外部源的磁耦合，通过蒸发超导接地层到衬底的背面。我们报告的发展光刻液晶在1-5 MHz的范围内使用FDM系统。这些谐振器将用于CMB极化实验，如Polarbear-2，Simons Array和SPT-3G。现有FDM系统的复用系数高达16 ×。我们将扩展报告为40$$\times $$×，即，Polarbear-2和68$\times $$×，即，SPT-3G。我们提出了北极熊-2的LC电路的设计标准，制造技术，和测试。将讨论诸如产量、频率精度、损耗和空间相邻通道之间的互感等问题。
Cosmic microwave background (CMB) polarization experiments are increasing the number of transition edge sensor (TES) bolometers to increase sensitivity. In order to maintain low thermal loading of the sub-Kelvin stage, the frequency-domain multiplexing (FDM) factor has to increase accordingly. FDM is achieved by placing TES bolometers in series with inductor–capacitor (LC) resonators, which select the readout frequency. The multiplexing factor can be raised with a large total readout bandwidth and small frequency spacing between channels. The inductance is kept constant to maintain a uniform readout bandwidth across detectors, while the maximum acceptable value is determined by bolometer stability. Current technology relies on commercially available ceramic chip capacitors. These have high scatter in their capacitance thereby requiring large frequency spacing. Furthermore, they have high equivalent series resistance (ESR) at higher frequencies and are time consuming and tedious to hand assemble via soldering. A solution lies in lithographed, planar spiral inductors (currently in use by some experiments) combined with interdigitated capacitors on a silicon (Si) substrate. To maintain reasonable device dimensions, we have reduced trace and gap widths of the LCs to 4 $$\upmu $$μm. We increased the inductance from 16 to 60 $$\upmu $$μH to achieve a higher packing density, a requirement for FDM systems with large multiplexing factors. Additionally, the Si substrate yields low ESR values across the entire frequency range and lithography makes mass production of LC pairs possible. We reduced mutual inductance between inductors by placing them in a checkerboard pattern with the capacitors, thereby increasing physical distances between adjacent inductors. We also reduce magnetic coupling of inductors with external sources by evaporating a superconducting ground plane onto the backside of the substrate. We report on the development of lithographed LCs in the 1–5 MHz range for use with FDM systems. These resonators will be used by CMB polarization experiments such as Polarbear-2, Simons Array, and SPT-3G. Existing FDM systems have multiplexing factors up to 16$$\times $$×. We report the extension to 40$$\times $$×, i.e., Polarbear-2, and 68$$\times $$×, i.e., SPT-3G. We present the design criteria of Polarbear-2’s LC circuits, the fabrication techniques, and the testing. Concerns such as yield, accuracy in frequency, loss, and mutual inductance between spatially neighboring channels will be discussed.
影响因子：
1.6
作者：
Dobbs, M. A.;Lueker, M.;Williamson, R.
通讯作者：
Williamson, R.