Development of a time-of-flight low-energy neutral particle analyzer for EAST tokamak.
Development of a time-of-flight low-energy neutral particle analyzer for EAST tokamak.
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DOI：
10.1063/1.5038936
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发表时间：
2018-10
期刊：
影响因子：
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通讯作者：
L. Mu;R. Ding;Y. Zhu;J. Chen;S. Li
中科院分区：
文献类型：
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作者：
L. Mu;R. Ding;Y. Zhu;J. Chen;S. Li
为了了解中性粒子对第一壁的侵蚀效应，基于飞行时间法研制了一台用于实验先进超导托卡马克(EAST)的低能中性粒子分析仪(LENPA)。将安装在东中面的LENPA主要由一个斩波子系统、一个3米长的飞行管、两套探测器组件以及数据采集和处理、真空、电源和控制子系统组成。中性外流在1μS时间尺度上由开槽转盘选通，转盘由涡轮分子泵改装而成的真空兼容电机驱动。一束He-Ne激光通过圆盘狭缝投射，用雪崩光电二极管模块记录斩波狭缝打开的瞬间。轴上电子倍增器探测被斩波的中性粒子，中心穿孔铜-铍板被用来将发射的二次电子引导到离轴电子倍增器中。紫外光通过CuBe板中心孔发射的紫外光产生的共轴电子倍增器的辐射峰，为记录斩波缝隙的开启时间提供了一种替代方法。在附加4TB快速存储卡的情况下，通过连续使用一块Gage采集卡，实现了1GS/S采样率。来自EAST的LENPA数据和中性粒子材料侵蚀实验将被用于对模拟结果进行基准测试，以便更好地预测未来的聚变堆，如热核实验堆和中国聚变工程试验堆。
To understand the erosion effect of neutral particles on the first wall, a low energy neutral particle analyzer (LENPA), based on the time-of-flight method, has been developed for the Experimental Advanced Superconducting Tokamak (EAST). The LENPA to be installed in the EAST mid-plane mainly consists of a chopper sub-system, a 3 m long flight tube, two sets of detector assemblies, and data acquisition and processing, vacuum, power supply, and control sub-systems. The neutral outflux is gated in bunches of 1 μs time scale by a slotted rotating disc which is driven by a vacuum compatible motor modified from a turbomolecular pump. A He-Ne laser beam is projected through the disc slit to record the instants of chopper slits opening with an avalanche photodiode module. An on-axis electron multiplier detects chopped neutrals, and a central perforated Cu-Be plate is employed to channel the emitted secondary electrons into an off-axis electron multiplier. The radiation peaks of on-axis electron multiplier caused by UV photons projected through the central hole of the Cu-Be plate provide an alternative way to record the chopper slits' opening time. With an additional 4 TB fast memory card, 1 GS/s sampling rate has been realized by using a GaGe acquisition card continuously. The LENPA data from the EAST together with neutral particle material erosion experiments will be used to benchmark the simulation results for better predictions on future fusion reactors, such as ITER and China Fusion Engineering Test Reactor (CFETR).