Deposition; PFC tile; HL-2A; LIBS; QMB;DIVERTOR TILES; ASDEX UPGRADE; CARBON; JET; EROSION/DEPOSITION; CODEPOSITION; EROSION; WALL
Since the divertor geometry of a tokamak has a strong impact on the material erosion and deposition on the wall and HL-2A has a unique divertor configuration, it is necessary to investigate the material deposition pattern in HL-2A although a few results on other tokamakS have already been published. In this paper, tiles retrieved from the vessel are analyzed ex-situ by sIMS, SEM and laser-induced breakdown spectroscopy (LIBS). And deposition behind the lower divertor is in-situ measured by a quartz crystal microbalance (QMB). The deposition in HL-2A displays a complex pattern and clear localization characteristic. The thickness of the deposition layer varies in the range of 0-4 mu m. And in-situ diagnostic of QMB indicates that the average thickness of the deposition layer per pulse is over ten nanometers. In addition, the results imply that Si, Fe and D have different behaviors during the material deposition in HL-2A. (C) 2016 Elsevier B.V. All rights reserved.