论文标题
MMT的近红外金字塔传感器
A Near-Infrared Pyramid Wavefront Sensor for the MMT
论文作者
论文摘要
MMTO自适应光学外球星表征系统（MAP）是亚利桑那州霍普金斯山上的6.5米MMT天文台的持续升级。地图包括升级的自适应次级镜（ASM），升级到白羊座光谱仪以及一个新的AO系统，该系统包含光学和近红外（NIR； 0.9-1.8 UM）Pyramid波前传感器（PYWFS）。 NIR PYWFS将利用与Saphira检测器结合的IR优化双金字塔：低阅读噪声电子雪崩光电二极管（EAPD）阵列。通过允许使用红色导向星（例如，银河平面中的K＆M-dwarfs或高度模糊的星星），该NIR PYWF将通过一个数量级来改善地图的天空覆盖范围。迄今为止，定制设计的低温Saphira摄像头已经完全表征，可以在高雪崩增益下达到子电子读取噪声。为了在交付到天文台之前在闭环环境中测试相机的性能，设计和构造了AO测试台。除了测试Saphira的性能外，测试床还将用于测试并进一步开发MMTO ASM的Sky校准程序。我们将报告我们的NIR PYWF，Saphira在测试台上的闭环性能以及ASM校准程序的状态。
The MMTO Adaptive optics exoPlanet characterization System (MAPS) is an ongoing upgrade to the 6.5-meter MMT Observatory on Mount Hopkins in Arizona. MAPS includes an upgraded adaptive secondary mirror (ASM), upgrades to the ARIES spectrograph, and a new AO system containing both an optical and near-infrared (NIR; 0.9-1.8 um) pyramid wavefront sensor (PyWFS). The NIR PyWFS will utilize an IR-optimized double pyramid coupled with a SAPHIRA detector: a low-read noise electron Avalanche Photodiode (eAPD) array. This NIR PyWFS will improve MAPS's sky coverage by an order of magnitude by allowing redder guide stars (e.g. K & M-dwarfs or highly obscured stars in the Galactic plane) to be used. To date, the custom designed cryogenic SAPHIRA camera has been fully characterized and can reach sub-electron read noise at high avalanche gain. In order to test the performance of the camera in a closed-loop environment prior to delivery to the observatory, an AO testbed was designed and constructed. In addition to testing the SAPHIRA's performance, the testbed will be used to test and further develop the proposed on-sky calibration procedure for MMTO's ASM. We will report on the anticipated performance improvements from our NIR PyWFS, the SAPHIRA's closed-loop performance on our testbed, and the status of our ASM calibration procedure.
