面向CMB偏振实验的220 GHz钛超导TES探测器技术研究

Development of a 220 GHz Ti superconducting TES detector array for CMB polarization experiment

高灵敏度超导相变边缘探测器(Transition Edge Sensor,TES)在宇宙微波背景(Cosmic Microwave Background,CMB)辐射B模偏振探测方面具有重要的应用前景。本文设计并制备了220 GHz频段8×8像元的天线耦合钛超导TES探测器,实验表征了刻蚀前钛超导TES探测器的低温热导和噪声特性。实验结果显示,钛超导TES探测器低温电声相互作用主导热导约为485.4 pW/K,同时钛超导TES探测器噪声等效功率优于5×10^(-17)W/Hz^(0.5)。原理上,钛超导TES探测器热导在刻蚀后会进一步减小,理论计算出刻蚀后钛超导TES探测器的热导约为38 pW/K,同时,其热起伏等效噪声功率理论值约为9.2×10^(-18)W/Hz^(0.5),因此,钛超导TES探测器在刻蚀后的噪声等效功率性能会进一步提升。

High-sensitivity superconducting transition edge sensor(TES)detectors have significant application prospects in the detection of the B-mode polarization of cosmic microwave background(CMB).In this study,we developed a 220 GHz antenna-coupled titanium(Ti)superconducting TES detector array(8×8)using a leg supporting structure.Before the supporting legs were fabricated,we measured the thermal conductance and the noise equivalent power(NEP)of the Ti superconducting TES detector.The measurement results show that the thermal conductance of the Ti superconducting TES detector,primarily determined by the electron-phonon interaction in the superconducting Ti microbridge,is approximately 485.4 pW/K.Moreover,the NEP of the Ti superconducting TES detector is approximately 5×10^(-17)W/Hz^(0.5).In principle,the thermal conductance of the Ti superconducting TES detector can be further reduced after its supporting legs are fabricated,which is approximately 38 pW/K.Meanwhile,the thermal fluctuation noise of the detector after its supporting legs are fabricated is approximately 9.2×10^(-18)W/Hz^(0.5).Thus,the noise performance can be further improved.