Modeling TES Nonlinearity Induced by a Rotating HWP in a CMB Polarimeter
Modeling TES Nonlinearity Induced by a Rotating HWP in a CMB Polarimeter
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对 CMB 旋光计中旋转 HWP 引起的 TES 非线性进行建模
DOI：
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发表时间：
2022
影响因子：
2
通讯作者：
N. Katayama
中科院分区：
文献类型：
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作者：
Tommaso Ghigna;T. Matsumura;Yukiko Sakurai;R. Takaku;K. Komatsu;S. Sugiyama;Y. Hoshino;N. Katayama
大多数即将进行的 CMB 实验都计划部署几千到几十万个 TES 测辐射热计，以大幅提高灵敏度并揭示 B 模式信号。微分系统效应和 1/ f 噪声是实现这一结果需要克服的两个挑战。近年来，旋转半波片作为减轻这些影响的解决方案变得越来越流行，特别是对于那些针对最大角度尺度的实验。然而，当采用旋转 HWP 时，可能会出现其他影响。在本文中，我们重点关注 HWP 同步信号，该信号是由用作望远镜系统第一个光学元件的旋转低温多层蓝宝石 HWP 引起的偏振泄漏强度造成的。我们使用 LiteBIRD LFT 作为案例研究，分析这些杂散信号与 TES 测辐射热计之间的相互作用，以确定该信号是否会污染测辐射热计响应。我们展示了几种不同 TES 模型假设和不同杂散信号幅度的模拟结果。对这些效应进行建模对于找出可以容忍的泄漏水平并最大限度地减少测辐射热计响应的非线性效应至关重要。
Most upcoming CMB experiments are planning to deploy between a few thousand and a few hundred thousand TES bolometers in order to drastically increase sensitivity and unveil the B -mode signal. Differential systematic effects and 1/ f noise are two of the challenges that need to be overcome in order to achieve this result. In recent years, rotating half-wave plates have become increasingly more popular as a solution to mitigate these effects, especially for those experiments that are targeting the largest angular scales. However, other effects may appear when a rotating HWP is being employed. In this paper, we focus on HWP synchronous signals, which are due to intensity to polarization leakage induced by a rotating cryogenic multilayer sapphire HWP employed as the first optical element of the telescope system. We use LiteBIRD LFT as a case study and we analyze the interaction between these spurious signals and TES bolometers, to determine whether this signal can contaminate the bolometer response. We present the results of simulations for a few different TES model assumptions and different spurious signal amplitudes. Modeling these effects is fundamental to find what leakage level can be tolerated and minimize nonlinearity effects of the bolometer response.