Optical performance of the BICEP2 Telescope at the South Pole
Optical performance of the BICEP2 Telescope at the South Pole
复制标题
南极 BICEP2 望远镜的光学性能
DOI：
10.1117/12.857868
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发表时间：
2010
期刊：
影响因子：
23.2
通讯作者：
C. L. Wong
中科院分区：
文献类型：
--
作者：
R. Aikin;P. Ade;S. Benton;J. Bock;J. A. Bonetti;J. Brevik;C. Dowell;L. Duband;J. Filippini;S. Golwala;M. Halpern;V. Hristov;K. Irwin;J. Kaufman;B. Keating;J. Kovac;C. Kuo;A. Lange;C. Netterfield;H. Nguyen;R. W. Ogburn;A. Orlando;C. Pryke;S. Richter;J. Ruhl;M. Runyan;C. Sheehy;S. Stokes;R. Sudiwala;G. Teply;J. Tolan;A. Turner;P. Wilson;C. L. Wong
Bicep 2在2009-2010年南极夏季部署到南极，现在正在绘制宇宙微波背景（CMB）的偏振，寻找暴胀宇宙学的证据。Bicep 2属于一类新的望远镜，包括凯克（地面）和蜘蛛（气球），遵循Bicep的战略，采用小，冷，轴上折射光学。这种常见的设计提供了关键的优势，理想的目标偏振签名从膨胀，包括：（i）一个大的视野，允许大量的光收集能力，尽管小孔径，同时仍然解决度尺度偏振的CMB;（ii）液态氦冷却的光学和冷停止，允许低，稳定的仪器加载;（三）能够使整个望远镜绕着地球旋转;（四）有挡板的主孔径，减少旁瓣拾取;（五）能够利用地面光源确定望远镜远场光学性能的特征。我们详细描述了最后这些优点，包括我们的努力，以测量主波束形状，正交极化对之间的波束匹配，极化效率和响应角，旁瓣拾取，鬼成像。我们这样做与地面极化微波源安装在远场以及天文校准器。最终，Bicep 2对暴胀引起的CMB极化的敏感性将依赖于对这些光束特征的精确校准。
Bicep2 deployed to the South Pole during the 2009-2010 austral summer, and is now mapping the polarization of the cosmic microwave background (CMB), searching for evidence of inflationary cosmology. Bicep2 belongs to a new class of telescopes including Keck (ground-based) and Spider (balloon-borne) that follow on Bicep's strategy of employing small, cold, on-axis refracting optics. This common design provides key advantages ideal for targeting the polarization signature from inflation, including: (i) A large field of view, allowing substantial light collecting power despite the small aperture, while still resolving the degree-scale polarization of the CMB; (ii) liquid helium-cooled optics and cold stop, allowing for low, stable instrument loading; (iii) the ability to rotate the entire telescope about the boresight; (iv) a baffled primary aperture, reducing sidelobe pickup; and (v) the ability to characterize the far field optical performance of the telescope using ground-based sources. We describe the last of these advantages in detail, including our efforts to measure the main beam shape, beammatch between orthogonally-polarized pairs, polarization efficiency and response angle, sidelobe pickup, and ghost imaging. We do so with ground-based polarized microwave sources mounted in the far field as well as with astronomical calibrators. Ultimately, Bicep2's sensitivity to CMB polarization from inflation will rely on precise calibration of these beam features.