Studies of aluminum erosion by neutral particles using quartz crystal microbalance and low energy neutral particle analyzer on EAST

The neutral-induced material erosion is still an unsolved issue for ITER and future reactors, which influences the lifetime of the first wall material and tritium retention rate. A low energy neutral particle analyzer (LENPA) and a quartz crystal microbalance (QMB) were recently installed together on the equatorial port of sector H in EAST to study neutral-induced material erosion. The QMB can provide real-time and in-situ measurements on the erosion process of the wall material, while the neutral energy spectrum given by LENPA can help to calculate the material erosion rate for comparison with QMB results. In the 2021 EAST summer campaign, neutral-induced Al erosion was successfully studied with the two available diagnostics for the first time. In a series of long-pulse discharges, the average Al erosion rates measured by the QMB are consistent with the theoretical calculations using the LENPA data. Furthermore, the changes in plasma density, heating power and the real-time lithium powder injection result in different neutral flux and energy, which lead to changes in the neutral-induced material erosion rates.