MRI: Development of a State-of-the-Art Multiband Receiver for Arizona Radio Observatory's New ALMA Antenna

MRI：为亚利桑那射电天文台的新型 ALMA 天线开发最先进的多频段接收器

• 批准号: 1531366
• 负责人: Lucy Ziurys
• 金额: $ 96.13万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2021-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1531366&HistoricalAwards=false
• 关键词: MRI; Development; State; Art; Multiband

As part of the development phase of the Atacama Large Millimeter Array (ALMA), two 12 meter ALMA prototype antennas (APA) were constructed for evaluation and testing, and installed at the National Radio Astronomy Observatory (NRAO) Very Large Array (VLA) site in Socorro, New Mexico. After completion of the ALMA testing and evaluation phase, the Arizona Radio Observatory (ARO) at the University of Arizona (UA) acquired one of the two APA telescopes. After acquisition, the UA moved their APA to Kitt Peak, replacing the 40-year-old 12-m telescope, and rechristening the telescope as the new Arizona Radio Observatory (ARO) 12 m. The subject proposal funds a modern, multi-wavelength receiver system which will realize the full scientific potential of the new ARO 12 m antenna. The receiver will cover the 1-4 mm wavelength range in four separate bands, and will enable a broad range of astronomical research including spectroscopy of molecular clouds and planetary nebulae, astrobiological studies of disks and pre-biotic molecules, and the study of black holes. The new receiver and 12 m antenna will have a broad user base with U.S. astronomers and scientists from universities and national labs, the Event Horizon Telescope consortium, and the European Southern Observatory (ESO). As part of this program ARO will allocate 28 days of observing time per year to the general U.S. community to access ARO's unique northern hemisphere observing capability and to enable pathfinder science for ALMA. The program will incorporate significant student training at all levels, from high school through graduate school. This telescope, along with the ARI 10 m telescope on Mt Graham, are perhaps the only remaining general purpose radio telescopes operated by a US university. As such, they are among the few remaining opportunities for direct student involvement in radio telescope instrumentation and operations. The dual-polarization 4-band receiver will cover the astronomically important atmospheric windows at 1, 2, 3, and 4 mm wavelength regions well suited to the Kitt Peak site. The 3 (84-116 GHz), 2 (130-180 GHz) and 1 mm (211-275 GHz) bands will employ ALMA-type, sideband-separating (SBS), superconducting (SIS) mixers, which represent the world's best in sensitivity and stability. SBS 2 mm mixers will be developed in collaboration with the National Radio Astronomy Observatory (NRAO) Central Development Lab (CDL) to cover a band scientifically important and well matched to the Kitt Peak site. The mixer chip will be a series array of four SIS junctions, similar to ALMA Band 6, and will be fabricated by the University of Virginia Microfabrication Lab (UVML). The 4 mm band (67-90 GHz) will utilize NRAO HFET amplifiers, previously tested on the old ARO 12 m. This system will also be SBS through an E-band down-converter developed by ARO. The 3 mm mixers are already in ARO's possession and the 1 mm devices will be obtained from NRAO. The mixers/amplifiers will be mounted in the same dewar using a modular design with each band and associated optics positioned on a separate plate. The receiver system will bolt onto the flange of the antenna cabin at the secondary focus. The spectral-line control system is fully operational at the new 12 m and will accommodate the new receiver with minimal modification. The new receiver will be used mainly for spectroscopic observations of interstellar and circumstellar molecules, and will: i) cover important molecular transitions, such as the J=1 - 0 lines of CO, HCN, N2H+, H2CO, and HCO+, used widely as density and temperature tracers in interstellar gas; and ii) provide wider frequency coverage necessary for many astrochemical programs. A major focus will be the investigation of the extent of molecular matter in the Galaxy. The subject work will redefine translucent cloud boundaries using low-level CO emission, characterize dense cloud cores chemically and physically, probe the sky as seen by Planck, and investigate hybrid gaseous/debris disks. The surprisingly rich chemical content of planetary nebulae and its connection to the diffuse interstellar medium will be further investigated. Combined with laboratory spectroscopy, the molecular carriers of the biogenic element phosphorus will be sought. The ARO 12 m will also join the Event Horizon Telescope for 1 mm VLBI observations, improving overall sensitivity and adding an intermediate baselines for probing the larger scale structure around black holes.

作为阿塔卡马大型毫米波天线阵（阿尔马）研制阶段的一部分，建造了两个12米阿尔马原型天线（阿帕）进行评估和测试，并安装在新墨西哥州索科罗的国家射电天文台（NRAO）甚大天线阵（VLA）站点。在完成阿尔马的测试和评估阶段后，亚利桑那大学的亚利桑那射电天文台（ARO）获得了两台阿帕望远镜中的一台。收购后，美国将他们的阿帕搬到了基特峰，取代了40岁的12米望远镜，并将望远镜重新命名为新的亚利桑那射电天文台（ARO）12米。该主题提案资助了一个现代化的多波长接收系统，该系统将实现新ARO 12米天线的全部科学潜力。该接收器将覆盖1-4毫米波长范围的四个不同波段，并将能够进行广泛的天文学研究，包括分子云和行星状星云的光谱学研究、盘和前生物分子的天体生物学研究以及黑洞研究。新的接收器和12米天线将拥有广泛的用户群，包括来自大学和国家实验室的美国天文学家和科学家，Event Horizon Telescope联盟和欧洲南方天文台（ESO）。作为该计划的一部分，ARO每年将向美国公众分配28天的观测时间，以获得ARO独特的北方半球观测能力，并为阿尔马提供开拓者科学。该计划将包括从高中到研究生院的各级学生的重要培训。这台望远镜，沿着位于格雷厄姆山的ARI 10米望远镜，可能是美国大学唯一剩下的通用射电望远镜。因此，他们是为数不多的直接学生参与射电望远镜仪器和操作的机会之一。 双偏振4波段接收器将覆盖非常适合基特峰站点的1、2、3和4毫米波长区域的天文学重要大气窗口。3（84-116 GHz）、2（130-180 GHz）和1 mm（211-275 GHz）频段将采用ALMA型、边带分离（SBS）、超导（SIS）混频器，这些混频器代表了世界上最好的灵敏度和稳定性。SBS 2毫米混频器将与国家射电天文台（NRAO）中央开发实验室（CDL）合作开发，以覆盖科学上重要的波段，并与Kitt Peak站点相匹配。该混频器芯片将是一个由四个SIS结组成的串联阵列，类似于阿尔马Band 6，并将由弗吉尼亚大学微加工实验室（UVML）制造。4毫米波段（67-90 GHz）将使用NRAO HFET放大器，之前在旧ARO 12 m上进行了测试。该系统还将通过ARO开发的E波段下变频器进行SBS。3毫米混频器已经在ARO的拥有和1毫米设备将获得从NRAO。混频器/放大器将安装在同一杜瓦瓶中，采用模块化设计，每个波段和相关光学器件位于单独的板上。接收器系统将在第二焦点处用螺栓固定在天线舱的凸缘上。谱线控制系统在新的12米处全面运作，将以最小的改动容纳新的接收器。新的接收器将主要用于星际和拱星分子的光谱观测，并将：i）覆盖重要的分子跃迁，如CO，HCN，N2 H+，H2 CO和HCO+的J=1 - 0线，广泛用作星际气体的密度和温度示踪剂; ii）提供许多天体化学计划所需的更宽的频率覆盖范围。一个主要的重点将是调查银河系中分子物质的范围。本课题的工作将使用低水平CO排放重新定义半透明云的边界，从化学和物理上表征致密云核，探测普朗克所看到的天空，并研究混合气体/碎片盘。行星状星云令人惊讶的丰富化学成分及其与弥漫星际介质的联系将得到进一步研究。结合实验室光谱学，寻找生源元素磷的分子载体。ARO 12 m还将加入Event Horizon Telescope，进行1 mm VLBI观测，提高整体灵敏度，并增加中间基线，用于探测黑洞周围的更大尺度结构。