Optical alignment of the high-precision UV spectro-polarimeter (CLASP2)
Optical alignment of the high-precision UV spectro-polarimeter (CLASP2)
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高精度紫外分光旋光计 (CLASP2) 的光学对准
DOI：
10.1117/12.2313056
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
Trujillo Bueno Javier
中科院分区：
文献类型：
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作者：
Song Donguk;Ishikawa Ryoko;Kano Ryouhei;Yoshida Masaki;Tsuzuki Toshihiro;Uraguchi Fumihiro;Shinoda Kazuya;Hara Hirohisa;Okamoto Takenori J.;Auchere Frederic;McKenzie David E.;Rachmeler Laurel A.;Trujillo Bueno Javier
色球层谱偏振仪（CLASP2）是我国继色球莱曼- α谱偏振仪（CLASP1）成功后的下一个探空火箭实验。CLASP2计划于2019年发射，目标是在280 nm附近实现Mg ii h和k线的线和圆偏振的高精度测量（< 0.1%），其线核起源于太阳上层色球层。CLASP2分光偏振光计遵循了CLASP1仪器非常成功的设计理念，并进行了最小的修改。制作了一种曲率半径与CLASP1光栅相同，但尺密度不同的新型光栅。这允许我们本质上重用CLASP1的机械结构和光学布局。但由于CLASP2的观测波长是CLASP1的两倍，因此在摄像机前新增了一个放大光学系统，使CLASP2的焦距增加一倍，并保持与CLASP1相同的波长分辨率（0.01 nm）。同时，为了达到0.01 nm的波长分辨率，需要对光谱偏振计进行仔细的光学校准。因此，我们在CLASP1经验的基础上，建立了CLASP2光谱偏振仪的有效对准程序。在这里，我们详细解释了实现CLASP2光谱偏振计光学对准的方法，并通过与性能要求的比较讨论了我们的结果。
Chromospheric LAyer Spectro-Polarimeter (CLASP2) is our next sounding rocket experiment after the success of Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP1). CLASP2 is scheduled to launch in 2019, and aims to achieve high precision measurements (< 0.1 %) of the linear and circular polarizations in the Mg ii h and k lines near the 280 nm, whose line cores originate in the upper solar chromosphere. The CLASP2 spectro-polarimeter follows very successful design concept of the CLASP1 instrument with the minimal modification. A new grating was fabricated with the same radius of curvature as the CLASP1 grating, but with a different ruling density. This allows us to essentially reuse the CLASP1 mechanical structures and layout of the optics. However, because the observing wavelength of CLASP2 is twice longer than that of CLASP1, a magnifier optical system was newly added in front of the cameras to double the focal length of CLASP2 and to maintain the same wavelength resolution as CLASP1 (0.01 nm). Meanwhile, a careful optical alignment of the spectro-polarimeter is required to reach the 0.01 nm wavelength resolution. Therefore, we established an efficient alignment procedure for the CLASP2 spectro-polarimeter based on an experience of CLASP1. Here, we explain in detail the methods for achieving the optical alignment of the CLASP2 spectro-polarimeter and discuss our results by comparing with the performance requirements.