Speaker
Description
Two sets of Low Energy Neutral Particle Analyzers (LENPAs) and Quartz Crystal Microbalances (QMBs) have been deployed on EAST to investigate the erosion and deposition processes of first wall materials (FWMs) within magnetic shadow areas (MSAs). These processes affect the lifetime of the first wall components and the fuel retention in the device, thereby posing a potential threat to the safe and stable operation of the tokamaks. The LENPAs, located at the mid-planes of sectors C and H respectively, employ time-of-flight methodology to provide neutral energy spectra in the range of 20–3000 eV [1]. Each LENPA system comprises a chopper subsystem, a 3-meter-long flight tube, dual detector assemblies, along with dedicated data acquisition, vacuum, power supply, and control subsystems. The QMBs, situated at the mid-planes of sectors C and J, utilize the piezoelectric effect to enable in situ, real-time measurements of nanogram-level erosion and deposition evolution on FWMs within MSAs [2]. A QMB instrument consists of a quartz crystal sensor, oscillator, and data acquisition system. This article provides a detailed description of the overall design layout, functions, system composition, and application in experiments of the LENPAs and QMBs on EAST. By integrating LENPA and QMB diagnostics, extensive investigations into erosion and deposition processes of FWMs have been conducted on EAST, including: the evolution of erosion and deposition of FMMs during wall conditioning experiment with lithium and boron as well as plasma operation [3]; measurements of erosion rates of aluminum and lithium induced by neutral particles during long-pulse, high-power plasma discharges [4]; and differences in FWMs erosion-deposition characteristics across radial MSAs [5]. The findings offer critical references for optimizing boronization strategies, predicting fuel retention, and estimating component lifetime in future fusion devices such as ITER.
References
[1] N. X. Liu et al., Nucl. Mater. Energy 33 (2022) 101258
[2] Y. Zhang et al., Rev. Sci. Instrum. 91 (2020) 076101
[3] Y. M. Liu et al., Nucl. Fusion 65 (2025) 096024
[4] L. Mu et al. Nucl. Mater. Energy 33 (2022) 101248
[5] L. Mu et al. Nucl. Fusion accepted (2026)