Stray light analysis and reduction for IFU spectrograph LLAMAS
Stray light analysis and reduction for IFU spectrograph LLAMAS
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IFU 光谱仪 LLAMAS 的杂散光分析和减少
DOI：
10.1117/12.2562999
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Simcoe, Robert A.
中科院分区：
文献类型：
--
作者：
Frostig, Danielle;Piotrowski, John;Clark, Kristin;Coppeta, David;Egan, Mark D.;Furész, Gábor;Gabutti, Michelle;Masterson, Rebecca A.;Malonis, Andrew;Simcoe, Robert A.
大透镜阵列麦哲伦光谱仪（LLAMAS）是一个集成场单元（IFU）光谱仪，作为6.5米麦哲伦望远镜的设施仪器正在建设中。对于每个指向，LLAMAS通过密集排列的微透镜+光纤阵列和复制的低成本光谱仪，在37“x37”天体立体角上提供2400光谱（λ =350-970nm），分辨率为2000。我们的主要科学目标之一是通过发射Lyα来研究环星系气体。为了达到观测所需的信噪比，LLAMAS必须将到达探测器的杂散光降至最低：漫射散射光必须保持在天空通量的0.25%以下，鬼影图像不得超过源信号的0.1%。我们使用光子工程公司的FRED光学工程软件对简化的LLAMAS模型进行了非顺序光线跟踪分析。重点研究了体相位全息光栅和光纤焦比退化产生的杂散光。通过分析，我们讨论了挡板的设计和制造，以掩盖杂散光的主要来源。此外，我们在相机内部开发了一个备用安装环系统，可以根据需要快速添加预制挡板。最后，我们报告了具有上述杂散光干预的2相机LLAMAS原型的实验室性能。
The Large Lenslet Array Magellan Spectrograph (LLAMAS) is an Integral Field Unit (IFU) spectrograph under construction as a facility instrument for the 6.5-meter Magellan Telescopes. For each pointing, LLAMAS delivers 2400 optical spectra (λ =350-970nm) over a 37”x37” celestial solid angle with a resolution of 2000 through a densely packed microlens+fiber array and replicated low-cost spectrographs. One of our main science goals is to study circumgalactic gas through Lyα emission. To achieve the required signal-to-noise ratio for these observations, LLAMAS must minimize stray light reaching the detector: diffuse scattered light must stay below 0.25% of sky flux and ghost images must not exceed 0.1% of the source signal. We present a non-sequential ray tracing analysis of a simplified LLAMAS model using Photon Engineering’s FRED Optical Engineering Software. We focus on stray light resulting from the volume phase holographic grating and from focal ratio degradation of the fibers. The analysis feeds into a discussion of the design and fabrication of baffles to mask the primary sources of stray light. Additionally, we develop a backup system of mounting rings inside of the cameras where pre-made baffles can be quickly added as needed. Finally, we report on the laboratory performance of a 2-camera LLAMAS prototype featuring the aforementioned stray light interventions.
LLAMAS 状态更新：适用于 6.5m 麦哲伦望远镜的宽视场可见光通带 IFU
DOI：
10.1117/12.2562803
发表时间：
2020
期刊：
Ground-based and Airborne Instrumentation for Astronomy VIII
影响因子：
--
作者：
Furész, Gábor;Simcoe, Robert A.;Egan, Mark D.;Malonis, Andrew;Masterson, Rebecca A.;Brown, Joshua;Cappiello, Gregory;Chesbrough, Christian;Clark, Kristin;Coppeta, David
通讯作者：
Coppeta, David