ITER core plasma thomson scattering diagnostic collection optics design

IF 1.9 3区工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY

Fusion Engineering and Design Pub Date : 2025-05-30 DOI:10.1016/j.fusengdes.2025.115194

M. Amarika , G. Beaskoetxea , A. Estevez , M. Roldán , A. María , G. Murga , L. Sanchez , U. Walach , J. Puig

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引用次数: 0

Abstract

The ITER Core Plasma Thomson Scattering (CPTS) diagnostic is conceived to measure the electron temperature and density with accuracies of 10 % and 5 %, respectively, at the Tokamak plasma core with a spatial resolution of a/30=66 mm (a plasma minor radius). For this purpose, a Nd:YAG 1064 nm laser is injected into the vacuum vessel during the plasma pulse, where it is scattered by the plasma electrons due to Thomson scattering (TS). The Collection Optics (CO) is in charge of acquiring the scattered photons at the plasma core (0 < r/a < 0.85) and guiding the light from the In-Vessel to the Ex-Vessel area where the laser chord is reimaged on a fibre backplane. The fibre bundles then transmit the collected light to the polychromators, where it is processed.

The design drivers and constraints for this system are diverse. Firstly, the CO shall provide a high optical transmission in the wavelength range of 400 -1050 nm. Secondly, there is a need to find a balance between collecting a sufficient amount of TS photons to ensure the required diagnostic performance while ensuring the shielding performance of the system. Thirdly, the CO design and material selection shall be compatible with the In-Vessel harsh environment and loading conditions and include a cleaning system for the First Mirror Unit (FMU). Finally, in terms of integration, the design needs to fit within existing available volumes allowing the integration of surrounding components and shall be able to compensate operational relative displacements between the In-Vessel and Ex-Vessel areas.

The proposed solution is based on a six mirrors dogleg configuration In-Vessel, and another two mirrors in a periscope configuration and a lens barrel composed of seven lenses Ex-Vessel. The analysis performed and the error budget has confirmed that the required optical performance of the CO is met, ensuring the required transmission, spatial resolution and coupling efficiency of the optical system.

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ITER核心等离子体汤姆逊散射诊断收集光学设计

ITER核心等离子体汤姆逊散射（CPTS）诊断被设计用于在托卡马克等离子体核心测量电子温度和密度，精度分别为10%和5%，空间分辨率为a/30=66 mm（等离子体小半径）。为此，在等离子体脉冲过程中，将Nd:YAG 1064 nm激光注入真空容器，在真空容器中被等离子体电子由于汤姆逊散射（TS）而散射。收集光学（CO）负责获取等离子体核心的散射光子(0 <；r / & lt;0.85)并将光从In-Vessel引导到exvessel区域，在那里激光弦在光纤背板上重新成像。然后，纤维束将收集到的光传输到多色器，在那里进行处理。该系统的设计驱动因素和约束因素是多种多样的。首先，CO应提供400 - 1050nm波长范围内的高光传输。其次，需要在收集足够数量的TS光子以确保所需的诊断性能与确保系统的屏蔽性能之间找到平衡。第三，CO设计和材料选择应与船内恶劣环境和装载条件相适应，并包括第一镜单元（FMU）的清洁系统。最后，在集成方面，设计需要适应现有的可用体量，允许周围组件的集成，并应能够补偿船内和船外区域之间的操作相对位移。所提出的解决方案是基于6个反射镜狗腿结构的in - vessel，潜望镜结构的另外2个反射镜和一个由7个透镜组成的透镜桶。通过分析和误差预算，确定了CO的光学性能满足要求，保证了光学系统的传输、空间分辨率和耦合效率。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Fusion Engineering and Design 工程技术-核科学技术

CiteScore

3.50

自引率

23.50%

发文量

275

审稿时长

3.8 months

期刊介绍： The journal accepts papers about experiments (both plasma and technology), theory, models, methods, and designs in areas relating to technology, engineering, and applied science aspects of magnetic and inertial fusion energy. Specific areas of interest include: MFE and IFE design studies for experiments and reactors; fusion nuclear technologies and materials, including blankets and shields; analysis of reactor plasmas; plasma heating, fuelling, and vacuum systems; drivers, targets, and special technologies for IFE, controls and diagnostics; fuel cycle analysis and tritium reprocessing and handling; operations and remote maintenance of reactors; safety, decommissioning, and waste management; economic and environmental analysis of components and systems.