Fuel retention measurements in Alcator C-Mod using accelerator-based in situ materials surveillance

This paper presents the first in situ time- and space-resolved measurements of deuterium (D) fuel retention in plasma-facing component (PFC) surfaces using Accelerator-based In-situ Materials Surveillance (AIMS) on the Alcator C-Mod tokamak. AIMS is a novel in situ materials diagnostic technique bas...

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Bibliographic Details
Main Authors: Lipschultz, Bruce, Hartwig, Zachary Seth, Barnard, Harold Salvadore, Sorbom, Brandon Nils, Lanza, Richard C, Stahle, Peter W, Whyte, Dennis G
Other Authors: Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
Format: Article
Language:en_US
Published: Elsevier 2017
Online Access:http://hdl.handle.net/1721.1/111187
https://orcid.org/0000-0003-4248-7876
https://orcid.org/0000-0002-2110-6766
https://orcid.org/0000-0002-4003-6089
https://orcid.org/0000-0002-9001-5606
Description
Summary:This paper presents the first in situ time- and space-resolved measurements of deuterium (D) fuel retention in plasma-facing component (PFC) surfaces using Accelerator-based In-situ Materials Surveillance (AIMS) on the Alcator C-Mod tokamak. AIMS is a novel in situ materials diagnostic technique based on the spectroscopic analysis of nuclear reaction products induced in PFC surfaces using an ∼MeV beam of deuterons from a compact linear accelerator in between plasma shots. AIMS measurements of D retention on inner wall PFCs were acquired during diverted and limited plasma operations and during wall conditioning experiments. Intershot measurements demonstrate the local erosion and codeposition of boron films on PFC surfaces with a constant ratio D/B. This is consistent with previous results suggesting that D codeposition with boron is insufficient to account for the net retention observed in Alcator C-Mod. Changes in deuterium concentration during boronization, electron cyclotron and glow cleanings were also measured.