登录
 机构网站
  1. 首页
  2. 情报产品
  3. 快讯详情

《美国空间大视场红外巡天望远镜（WFIRST）星冕仪通过第七轮里程碑评估》

  • 来源专题：天文仪器与技术信息
  • 编译者： zwg@niaot.ac.cn
  • 发布时间：2017-01-02

  • A Webex review of Milestone #7 for the WFIRST coronagraph technology programwas held on September 15, 2016. All five of the TAC members were able toparticipate in the review.

    Milestone #7 deals with the low noise detector requirements for the WFIRSTcoronagraph. When the noise requirements were specified several years ago, it wasnot clear if electron-multiplying CCDs (EMCCDs) would be suitable for use onWFIRST, or if the photon-counting readout technique would be applicable.

    As aresult of the error budget assigned to the detector at that time, the Milestone #7performance requirements for the detector and the readout electronics were set tobe a dark current less than 0.001 electrons/pixel/sec and a read noise less than 1electron/pixel/frame.

    Due largely to the decision to employ both EMCCDs andphoton counting threshold limits, both of these Milestone requirements have beenhandily met, even after exposure to radiation doses (multi-MEV protons) equivalentto over twice those expected during a six-year mission to and at L2.

    The measureddark current was 0.0007 electrons/pixel/sec, just below the requirement, and themeasured read noise was 1.7e-6 electrons/pixel/frame, nearly six orders ofmagnitude lower than required.

    In addition, the team demonstrated an ability tofurther adjust gains to deal with any unanticipated degradations, such as aging.While actual testing was conducted using COTS readout electronics, the TAC felt theteam’s design summarized for readout electronics based on space-heritagecomponents was sufficient at this time to support the milestone requirement fortesting with space-like electronics. Clearly both requirements of Milestone #7 havebeen met and exceeded.

    The tests also examined and reported on a number of othermeasures of the noise associated with the EMCCD/photon counting approach, inboth serial and parallel read-out mode, giving further support to the assertion thatthis approach should succeed.

    Meeting this Milestone on schedule implies that the project is still on its way tofinishing the WFIRST coronagraph Key Milestones on schedule. The TAC looksforward to learning about the progress made on the remaining two Key Milestones(#8 and #9), dealing with the OMC and PIAACMC coronagraph tests in the JPL HCIT,in both static and dynamic environments, the latter simulating the expectedperformance on a space telescope with pointing jitter.

    We thank Ben Parvin, Rick Demers, Leon Harding, and other WFIRST/AFTA-C teammembers for their presentations and comments during the review.

  • 原文来源：https://wfirst.gsfc.nasa.gov/science/sdt_public/wps/references/WFIRST-C-TAC-MS7-final.pdf
98浏览量
原文链接
相关报告

  • 《宽视场红外巡天望远镜WFIRST系外行星数据挑战#1》
    • 来源专题：天文仪器与技术信息
    • 编译者：zwg@niaot.ac.cn
    • 发布时间：2016-10-20
    • WFIRST当前处于Phase A 阶段，要定义其科学和仪器性能要求。 Welcome to the WFIRST Exoplanets Data Challenge #1! The WFIRST mission is currently in Phase A, during which time the science and instrument performance requirements will be defined for exoplanet imaging and spectroscopy. In order to provide the project with the best possible inputs before the end of Phase A in 2017, we are seeking participation from teams with spectral retrieval expertise through the WFIRST exoplanets data challenge. The Challenge will run from August 15 to November 15, 2016. The 2016 Challenge consists of a blind spectral retrieval exercise using simulated, extracted spectra for several known RV and/or hypothetical discovery exoplanets. The spectra will NOT need to be extracted from simulated IFS data. Instead, we will explore the impact of signal-to-noise ratio and spectral resolution on the detection/measurement of atmospheric abundances and other planet properties. Even with that relatively simple goal, we expect the Challenge to be non-trivial! Incentive to Participate: While defining the first space-borne exoplanet imaging mission is hopefully its own compelling reason for doing this, to make this a little more fun the WFIRST Data Challenge Science Investigation Team is offering travel expenses and registration costs for one person on each team that fully completes the Challenge (all four planets, all SNR and R values, all requested retrieval outputs) to attend the 2017 WFIRST Science Meeting, or another exoplanets meeting of his/her choice (up to $2000). Participation in the Challenge is contingent upon acceptance of terms which will be included in the invitation email. If you wish to participate, please register and you will be sent an invitation. If you have questions, please forward them to Margaret Turnbull and David Ciardi through the "Contact" link above. We look forward to working with you this Fall!
    130浏览量
    原文链接

  • 《美国TMT望远镜红外成像光谱仪获得里程碑进展》
    • 来源专题：天文仪器与技术信息
    • 编译者：zwg@niaot.ac.cn
    • 发布时间：2017-02-23
    • PASADENA, CA – Design of the Thirty Meter Telescope’s IRIS (InfraRed Imaging Spectrograph), recently achieved a major milestone. The IRIS design team successfully completed the first of two slated Preliminary Design Reviews, which spanned the complete opto-mechanical design for the instrument. Additionally, the full set of operational concepts as well as all system and subsystem level design requirements and interfaces were presented. IRIS is a first light instrument designed to operate in the near-infrared (0.84-2.4 μm). It will enable the broad study of astronomical objects by providing data sets that are exquisite in their detail. It will achieve an angular resolution 10 times better than images from the Hubble Space Telescope. As one of the highest angular resolution near-infrared instruments in the world, it will help usher in a new era of astronomical study. The instrument will sample the diffraction limit provided by the Thirty Meter Telescope at wavelengths greater than 1 μm. The IRIS design features an integral field spectrograph (R~4000), which itself provides two sampling techniques. The current sequential design also provides an imager with a 34"x34" field of view. Both the spectrograph and imager will take advantage of the high spatial resolution achieved with the Narrow-Field Infrared Adaptive Optics System (NFIRAOS). The review panel, chaired by Niranjan Thatte - Professor of Astrophysics at the University of Oxford - consisted of experts both external and internal to the project. It will be followed by the second IRIS Preliminary Design Review in late summer 2017, which will review the electrical and software designs as well as safety and quality assurance plans. The IRIS partnership collaborated for three and a half years, relying on strong cross cultural communication, design heritage and a clear scientific vision to produce the current design; culminating in a successful review. This established tenacity has positioned the IRIS team to tackle the design challenges ahead. The IRIS design consortium is a partnership between the University of California at Los Angeles (UCLA), the California Institute of Technology (Caltech), National Research Council (NRC) of Canada - Herzberg, National Astronomical Observatory of Japan (NAOJ), University of California at Santa Cruz (UCSC), University of California at San Diego (UCSD) and the Nanjing Institute of Astronomical Optics and Technology (NIAOT). James Larkin (UCLA), Principal Investigator and Shelley Wright (UCSD), Project Scientist are leading the instrument development program. The review meeting was held at the Thirty Meter Telescope International Observatory (TIO) project office in Pasadena, California. Through a combination of face-to-face and virtual participation, more than 50 astronomers and engineers from the IRIS team attended the review.
    202浏览量
    原文链接