CAMELS - The Cambridge Emission Line Surveyor for the Greenland Telescope

CAMELS - 格陵兰望远镜的剑桥发射线测量员

• 批准号: ST/L002221/1
• 负责人: Stafford Withington
• 金额: $ 39.71万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2014
• 资助国家: 英国
• 起止时间: 2014 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FL002221%2F1
• 关键词: CAMELS; Cambridge; Emission; Line; Surveyor

It is widely recognised that the development of a mature chip spectrometer technology, where each pixel in a focal-plane array is intrinsically capable of yielding detailed spectroscopic information, would revolutionise far-infrared and submm-wave(4 mm to 300 um) astronomy. Low spectral-resolution channels (R = 5-20) could be used for CMB and SZ astronomy, and for determining dust temperatures through simultaneous multicolour observations of continuum sources; medium spectral-resolution channels (R = 500-1000) could be used for wide-field blind surveys of high-redshift spectral-lines; and high spectral-resolution channels (R = 2000-4000) could be used for multiline mapping of molecular gas in star-forming regions and extended nearby galaxies. Once the core technology is available, a large number of pixels could be packed into arrays for mapping and surveys, or a small number of pixels could be positioned sparsely over a wide field of view to enable multi-object spectroscopy. Although a number of organisations are working on chip spectrometers, the international community is falling short of demonstrating science-grade observations. To some extent this situation has occurred because a significant amount time is needed on a submm-wave telescope to understand behaviour and refine designs. To address this situation, we propose to demonstrate a high-resolution (R = 3000) superconducting filter-bank spectrometer for the 70-115 GHz (4.3-2.6 mm) atmospheric window. The Cambridge Emission Line Surveyor (CAMELS) is a collaborative project between the Cavendish Laboratory and the Harvard Smithsonian Center for Astrophysics (CFA). CAMELS will be installed on the Greenland Telescope (GLT) and used to map isotopic abundances in low-z galaxies by measuring 12CO (vr = 115.271 GHz) and 13CO (vr =110.201 GHz) line strengths simultaneously. We will assess two slightly different designs: One will map bright lines from extended galaxies (z = 0.005 - 0.05) against high backgrounds (NEP = 2 x 10-17 WHz-1/2), and the other will detect faint lines from point sources (z = 0.05 - 0.12) against low backgrounds (NEP = 4 x 10-18 WHz-1/2). As well as being scientifically important, operation in the 70-115 GHz window will allow us to explore performance, without worrying about scheduling limitations imposed by the atmosphere.The elements of a chip spectrometer are easy to understand in principle, but the realisation of a complete instrument that is capable of making science-grade observations requires detailed knowledge. Our pixels will comprise a single-mode antenna, a bank of superconducting RF filters, coupling terminations to an array of Kinetic Inductance Detectors (KIDs), and a single superconducting readout line. All of these will be realised on a single wafer using multi-layer superconducting microcircuit technology. The chip will be read out using fast digital electronics and Software Defined Radio (SDR) techniques. The Cambridge Group runs a state of the art facility for manufacturing superconducting quantum sensors, and has considerable expertise in fabricating multi-layer microcircuits using bcc-Ta, beta-Ta, NbN, Nb, Al, Mo, Hf, Ir, Au, Cu, SiO, SiO2 films on Si substrates and SiN membranes. This facility will be used to realize the spectrometer modules.The outlook for the technology is considerable, and our programme contributes strongly to STFC's vision. All existing and planned ground-based and space-borne far-infrared observatories are completely reliant on superconducting imaging arrays and receivers. Superconducting device processing technology is now well established, and the next step is to produce microcircuits having complex on-chip functionality. For example, the ability to realise hyperspectral imaging where each pixel is capable of measuring the temperature of the continuum background and the strengths of certain widely space lines simultaneously would have a major impact on the design of future space telescopes.

人们普遍认为，成熟的芯片光谱仪技术的发展将彻底改变远红外和亚毫米波（4毫米至300微米）天文学，其中焦平面阵列中的每个像素本质上都能够产生详细的光谱信息。低光谱分辨率通道（R = 5-20）可用于 CMB 和 SZ 天文学，以及通过连续源的同时多色观测来确定尘埃温度；中等光谱分辨率通道（R = 500-1000）可用于高红移谱线的宽视场盲测；高光谱分辨率通道（R = 2000-4000）可用于恒星形成区域和附近扩展星系中分子气体的多线测绘。一旦核心技术可用，就可以将大量像素装入阵列中以进行测绘和勘测，或者可以将少量像素稀疏地放置在宽视场上以实现多目标光谱。尽管许多组织正在研究芯片光谱仪，但国际社会仍未能展示科学级的观测结果。在某种程度上，这种情况的发生是因为亚毫米波望远镜需要大量的时间来理解行为和完善设计。为了解决这种情况，我们建议展示一种适用于 70-115 GHz（4.3-2.6 mm）大气窗口的高分辨率（R = 3000）超导滤波器组光谱仪。剑桥发射线测量仪 (CAMELS) 是卡文迪什实验室和哈佛史密森天体物理中心 (CFA) 之间的合作项目。 CAMELS 将安装在格陵兰望远镜 (GLT) 上，通过同时测量 12CO (vr = 115.271 GHz) 和 13CO (vr =110.201 GHz) 线强度来绘制低 z 星系中的同位素丰度图。我们将评估两种略有不同的设计：一种将在高背景 (NEP = 2 x 10-17 WHz-1/2) 下绘制来自扩展星系 (z = 0.005 - 0.05) 的亮线，另一种将检测来自点的微弱线低背景 (NEP = 4 x 10-18 WHZ-1/2) 下的源 (z = 0.05 - 0.12)。除了在科学上很重要之外，在 70-115 GHz 窗口中运行将使我们能够探索性能，而不必担心大气施加的调度限制。芯片光谱仪的元件原则上很容易理解，但实现能够进行科学级观察的完整仪器需要详细的知识。我们的像素将包括一个单模天线、一组超导射频滤波器、一组动感电感探测器 (KID) 的耦合终端以及一条超导读出线。所有这些都将利用多层超导微电路技术在单个晶圆上实现。该芯片将使用快速数字电子技术和软件定义无线电（SDR）技术进行读取。剑桥集团拥有最先进的超导量子传感器制造设施，并在使用 bcc-Ta、β-Ta、NbN、Nb、Al、Mo、Hf、Ir、Au、Cu 制造多层微电路方面拥有丰富的专业知识、Si 衬底和 SiN 膜上的 SiO、SiO2 薄膜。该设施将用于实现光谱仪模块。该技术的前景非常可观，我们的计划为 STFC 的愿景做出了巨大贡献。所有现有和规划的地基和星载远红外观测站都完全依赖超导成像阵列和接收器。超导器件加工技术现已成熟，下一步是生产具有复杂片上功能的微电路。例如，实现高光谱成像的能力（其中每个像素能够同时测量连续背景的温度和某些宽空间线的强度）将对未来太空望远镜的设计产生重大影响。

项目成果

Electrothermal model of kinetic inductance detectors

动感电感探测器的电热模型

• DOI: 10.1088/0953-2048/28/4/045012
• 发表时间: 2014-11-06
• 期刊: Superconductor Science and Technology
• 影响因子: 3.6
• 作者: C. N. Thomas;S. Withington;D. Goldie
• 通讯作者: D. Goldie