Low-noise transition edge sensor (TES) for SAFARI instrument on SPICA
Low-noise transition edge sensor (TES) for SAFARI instrument on SPICA
复制标题
SPICA 上 SAFARI 仪器的低噪声过渡边缘传感器 (TES)
DOI：
10.1117/12.857725
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发表时间：
2010
影响因子：
1.8
通讯作者：
H. Hoevers
中科院分区：
文献类型：
--
作者：
P. Khosropanah;B. Dirks;M. Parra;M. Ridder;R. Hijmering;J. van der Kuur;L. Gottardi;M. Bruijn;M. Popescu;J. Gao;H. Hoevers
过渡边缘传感器（TES）是日本SPICA望远镜上SAFARI FIR成像光谱仪（焦平面阵列覆盖30 - 210 μm波长范围）的选定探测器。由于望远镜被冷却到<7 K，仪器的灵敏度受到探测器噪声的限制。因此，在所有要求中，灵敏度是一个至关重要的要求，在基础温度>50 mK时，灵敏度应达到低至3E-19 W/Hz ^0.5的NEP（噪声等效功率）。在SPICA平台上制作并表征了用于SAFARI仪器的低热导过渡边缘传感器（TES）。该器件是基于一个超导Ti/Au双层沉积在悬浮的SiN膜。器件的临界温度为155 mK。通过使用窄的SiN环状支撑结构实现了低热导率。所有的测量都是在不透光的盒子中进行的，这在很大程度上消除了背景辐射的负载。我们测量了器件在不同浴温下的电流-电压（IV）特性，并确定热导率（G）等于1.66 pW/K。该值对应于1 E-18 W/kHz的噪声等效功率（NEP）。在25 mK水浴温度下，在不同的偏压点上测量了电流噪声和复阻抗。测得的电（暗）NEP为2 E-18 W/kHz，这比我们从IV曲线得出的热导率所预期的高出约2倍。尽管使用了不透光的盒子，光子噪声仍然可能是这种多余噪声的来源。我们还测量了同一器件在几个偏置点的复阻抗。用一个简单的一阶热电模型对实验数据进行拟合，得到了相变中间的有效时间常数约为65 μs，热容为3- 4fJ/K
Transition edge sensor (TES) is the selected detector for the SAFARI FIR imaging spectrometer (focal plane arrays covering a wavelength range from 30 to 210 μm) on the Japanese SPICA telescope. Since the telescope is cooled to <7 K, the instrument sensitivity is limited by the detector noise. Therefore among all the requirements, a crucial one is the sensitivity, which should reach an NEP (Noise Equivalent Power) as low as 3E-19 W/Hz^0.5 for a base temperature of >50 mK. Also the time constant should be below 8 ms. We fabricated and characterized low thermal conductance transition edge sensors (TES) for SAFARI instrument on SPICA. The device is based on a superconducting Ti/Au bilayer deposited on suspended SiN membrane. The critical temperature of the device is 155 mK. The low thermal conductance is realized by using narrow SiN ring-like supporting structures. All measurements were performed having the device in a light-tight box, which to a great extent eliminates the loading of the background radiation. We measured the current-voltage (IV) characteristics of the device in different bath temperatures and determine the thermal conductance (G) to be equal to 1.66 pW/K. This value corresponds to a noise equivalent power (NEP) of 1E-18 W/√Hz. The current noise and complex impedance is also measured at different bias points at 25 mK bath temperature. The measured electrical (dark) NEP is 2E-18 W/√Hz, which is about a factor of 2 higher than what we expect from the thermal conductance that comes out of the IV curves. Despite using a light-tight box, the photon noise might still be the source of this excess noise. We also measured the complex impedance of the same device at several bias points. Fitting a simple first order thermal-electrical model to the measured data, we find an effective time constant of about 65 μs and a thermal capacity of 3-4 fJ/K in the middle of the transition