Scalable 100 GHz focal plane arrays: a 16-pixel wideband array for the Green Bank Telescope

用于毫米波长光谱学的大型探测器阵列的开发为新发现提供了很好的机会，可能使分子线调查能够有效地绘制恒星形成气体的动态和分布，并在大面积的天空中具有高角度和光谱分辨率。 构建大型光谱阵列的挑战是技术性的，而不是基础性的：阵列中的每个像素必须是一个完整和独立的外差光谱仪。 在5-170 GHz（波长1.8-60 mm）的天文学重要频率范围内，基于高电子迁移率晶体管（HEMT）的放大器具有低噪声、低功耗、高可靠性、固有的宽带宽以及构建高光谱分辨率仪器的能力。 根据之前的NSF奖项，S。Church of斯坦福大学教授和她的合作者开发了必要的复杂制造技术，并使用单像素馈电喇叭、低噪声单片毫米波集成电路（MMIC）放大器和现场可编程门阵列（FPGA）作为信号处理组件，构建了这种仪器的原型组件。 目前的建议旨在将这一技术扩展到大规模生产和机器组装，目标是在国家射电天文台100米绿色银行望远镜（GBT）上进行W波段（85-116 GHz）观测的16通道Argus光谱仪。 虽然16像素探测器不能充分利用这种方法的潜力，但它与GBT提供的视场非常匹配，其可扩展的设计将为未来的阵列提供概念和制造技术的证明，其他望远镜上可能有数百个像素。 虽然不打算作为一个GBT设施的仪器，阿古斯将开放给一般天文学界的合作研究使用。 该项目还将通过直接参与仪器开发以及在地区社区学院和高中的持续推广工作来促进学生和年轻研究人员的培训。NSF天文科学部通过其先进技术和仪器计划为基于MMIC的多通道毫米波光谱仪的开发提供资金。

The development of large format detector arrays for millimeter-wavelength spectroscopy offers great opportunity for new discovery, potentially enabling molecular line surveys that efficiently map the dynamics and distribution of star-forming gas with high angular and spectral resolution over large areas of sky. The challenge to building large spectroscopic arrays is technical rather than fundamental: each pixel in the array must be a complete and independent heterodyne spectrometer. In the astronomically important frequency range of 5-170 GHz (wavelength 1.8-60 mm), amplifiers based on High Electron Mobility Transistors (HEMTs) offer low noise, low power dissipation, high reliability, inherently wide bandwidths, and the ability to build instruments with high spectral resolution. Under a previous NSF award, Dr. S. Church of Stanford Univ. and her collaborators developed the necessary complex fabrication techniques and constructed prototype components for such an instrument using single-pixel feed horns, low-noise Monolithic Millimeter-wave Integrated Circuit (MMIC) amplifiers, and Field Programmable Gate Arrays (FPGAs) as the signal-processing components. The current proposal aims to extend this technology toward mass-production and machine-assembly with the 16-channel Argus spectrometer targeted for W-band (85-116 GHz) observations at the 100m Green Bank Telescope (GBT) of the National Radio Astronomy Observatory. While a 16-pixel detector will not fully exploit the potential of this approach, it is well-matched to the field of view offered by the GBT and its scalable design will provide a proof of both concept and fabrication technique for future arrays with perhaps hundreds of pixels on other telescopes. Though not intended as a GBT facility instrument, Argus will be opened to collaborative research use by the general astronomical community. The project will also foster the training of students and young researchers through direct hands-on involvement in the instrument development as well as ongoing outreach efforts in area community colleges and high schools.Funding for the development of MMIC-based multi-channel mm-wave spectrometers is being provided by NSF's Division of Astronomical Sciences through its Advanced Technologies and Instrumentation program.