Development of the materials analysis and particle probe for Proto-MPEX

Abstract

The Prototype Material Plasma Exposure eXperiment (Proto-MPEX) is a linear plasma device being used in plasma source research and development (R&D) for the proposed MPEX. Once the R&D is completed, this device can also be used to perform plasma–material interaction studies. To perform these studies, a new materials analysis and particle probe (MAPP) has been constructed. The MAPP’s components are a sample holder and manipulator and a custom vacuum chamber with ports to facilitate surface chemistry diagnostics. The MAPP’s overall design enables rapid sample turnaround and in vacuo surface characterization. The surface analysis vacuum chamber has ports for x-ray photoelectron spectroscopy, thermal desorption spectroscopy, back-scatter ion scattering spectroscopy, forward-scatter ion scattering spectroscopy, and direct recoil spectroscopy. The sample manipulator and holder is a Lesker/UHV Multi-Centre Analytical Stage, which is used to place the samples in the exposure region of the Proto-MPEX or the analysis position in the MAPP vacuum chamber. The sample holder has a heating capability of up to 1200 °C for heated exposure and for desorption studies. In this work, we present the MAPP’s design and the first tungsten sample exposure with ex situ analysis that shows a surface deposition layer on the exposed target, highlighting the need for additional in situ measurements on the Proto-MPEX.

Numerical studies for plasmas of a linear plasma device HIT-PSI with geometry modified SOLPS-ITER

“…Comparing with tokamak divertors, LPD has significant advantages in cost-effectiveness, convenience of disassembly and target plate replacement, facilitating the evaluation of experimental data, and ability to operate under high heat load conditions with extended pulse durations. Consequently, numerous institutions have devised restrictive LPDs including Magnum-PSI, [2][3][4] MAGPIE, [5,6] GyM, [7,8] Proto-MPEX, [9,10] and MPS-LPD, [11,12] with the purpose of studying the physics underlying PWI and advancing divertor target materials. According to the heat load estimate of the ITER divertor, the target should be capable of withstanding at least a heat flux of 10 MW • m −2 .…”

“…To investigate the phenomena of PWI for establishing a controlled experimental setting to evaluate available divertor target materials, the linear plasma device parameters are needed to replicate as closely as possible the conditions in the tokamak divertor. Currently, only a few devices are available to simulate the divertor parameters or heat load in an ITERlike manner, e.g., Magnum-PSI, [2][3][4] Proto-MPEX, [9,10] and GAMMA10/PDX. [13,14] Recently, HIT-PSI, a linear plasma device with tesla magnetic confinement, has been developed at the Harbin Institute of Technology, [15] as depicted in Fig.…”