Enhancing GBT metrology to support high resolution 3mm molecular imaging for the U.S. Community

增强 GBT 计量学，支持美国社区的高分辨率 3mm 分子成像

• 批准号: 1836009
• 负责人: Felix Lockman
• 金额: $ 134.59万
• 依托单位: Associated Universities, Inc.
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-15 至 2022-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1836009&HistoricalAwards=false
• 关键词: Enhancing; GBT; metrology; support; resolution

The Green Bank Telescope (GBT) is the world's largest fully-steerable telescope and a unique asset for the US scientific community. Its surface, which is larger than a football field, must be adjusted very precisely to bring the incoming radio waves into focus, so the surface was designed with more than 2000 individual panels mounted on precise motors. The motors can move the panels to compensate for any deviations from the perfect shape. While this works quite well at night, it can be very difficult to make this adjustment during daylight hours, when sunlight falling on different parts of the dish causes temperature changes and unpredictable distortions that cannot currently be measured. These distortions limit use of the GBT at its highest operating frequencies, where tolerances on surface accuracy are the tightest. The current project will implement a laser ranging measurement system on the GBT that will measure any surface distortions very accurately, allowing the GBT to be focused precisely both day and night. This will increase the available usable time of the telescope at its highest operating frequencies by as much as 1,000 hours every year, with a corresponding increase in the scientific output of the GBT and its utility to the US scientific community for a broad range of investigations. The Green Bank Observatory also supports a wide range of public outreach activities through its visitor center. Enhancements to the Green Bank Telescope (GBT) metrology system are planned that will enable expanded operation in the 3mm wavelength band during daylight hours. This work will increase the usable telescope time at 3mm by as much as a factor of two, and increase available time on the molecule-rich inner Galactic plane and the Galactic center by up to a factor of four. Recent technological advances in commercial metrology make it possible to purchase a Terrestrial Laser Scanner (TLS) which, when mounted near the prime focus of the GBT, can scan the entire dish in one to two minutes, producing ~10 million data points with individual range accuracies of the order of a few mm. A least-squares fit to these data provides an estimate of the surface with accuracies ~30 microns rms, significantly better than the current method of "out-of-focus holography" and well in excess of the accuracy needed. The measured surface would be compared to the ideal surface to produce commands to the surface panel actuators to compensate for the thermal distortions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

绿色银行望远镜（GBT）是世界上最大的全面望远镜，也是美国科学界的独特资产。 它的表面比足球场大，必须非常精确地调整以使传入的无线电波成为焦点，因此该表面的设计是在精确的电动机上安装的2000多个单独的面板设计。 电动机可以移动面板以补偿与完美形状的任何偏差。 尽管这在晚上效果很好，但在白天的时间里进行调整可能非常困难，当阳光落在盘子上的不同部分会导致温度变化和目前无法测量的不可预测的扭曲时。 这些扭曲限制了GBT在其最高工作频率下的使用，在其表面准确性上的公差最紧。 当前的项目将在GBT上实现激光范围测量系统，该测量系统将非常准确地测量任何表面扭曲，从而使GBT可以精确地聚焦于白天和黑夜。 这将使望远镜在其最高运行频率下的可用可用时间每年增加1000小时，而GBT的科学输出及其对美国科学界的效用相应增加，以进行广泛的调查。绿色银行天文台还通过其游客中心支持广泛的公共外展活动。 计划对绿色银行望远镜（GBT）计量系统进行增强功能，该系统将在白天在3mm波长频段中扩大操作。这项工作将使3mm的可用望远镜时间增加多达两倍，并在富含分子的内部银河平面和银河系中心上增加可用时间，最高为四倍。 商业计量学方面的最新技术进步使得购买陆地激光​​扫描仪（TLS）是可能的，当安装在GBT的主要焦点附近时，可以在一到两分钟内扫描整个菜肴，从而产生约1000万个数据点，其单个范围的精确度的单个范围精确量的几个mm。适合这些数据的最小二乘提供了估计表面的精度约为30微米的RMS，明显好于当前的“异常全息图”的方法，并且超出了所需的准确性。将测得的表面与理想的表面进行比较，以对表面面板执行器产生命令，以补偿热扭曲。此奖项反映了NSF的法定任务，并被认为是通过基金会的知识分子和更广泛影响的审查标准来评估的值得支持的。