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Title: A hemispherical Langmuir probe array detector for angular resolved measurements on droplet-based laser-produced plasmas

In this work, a new diagnostic tool for laser-produced plasmas (LPPs) is presented. The detector is based on a multiple array of six motorized Langmuir probes. It allows to measure the dynamics of a LPP in terms of charged particles detection with particular attention to droplet-based LPP sources for EUV lithography. The system design permits to temporally resolve the angular and radial plasma charge distribution and to obtain a hemispherical mapping of the ions and electrons around the droplet plasma. The understanding of these dynamics is fundamental to improve the debris mitigation techniques for droplet-based LPP sources. The device has been developed, built, and employed at the Laboratory for Energy Conversion, ETH Zürich. The experimental results have been obtained on the droplet-based LPP source ALPS II. For the first time, 2D mappings of the ion kinetic energy distribution around the droplet plasma have been obtained with an array of multiple Langmuir probes. These measurements show an anisotropic expansion of the ions in terms of kinetic energy and amount of ion charge around the droplet target. First estimations of the plasma density and electron temperature were also obtained from the analysis of the probe current signals.
Authors:
; ; ;  [1]
  1. ETH Zürich, Laboratory for Energy Conversion, Sonneggstrasse 3, 8092 Zürich (Switzerland)
Publication Date:
OSTI Identifier:
22314692
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 85; Journal Issue: 9; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; ANISOTROPY; CHARGE DISTRIBUTION; CHARGED PARTICLE DETECTION; ELECTRON TEMPERATURE; ENERGY SPECTRA; EXTREME ULTRAVIOLET RADIATION; KINETIC ENERGY; LANGMUIR PROBE; LASER-PRODUCED PLASMA; MAPPING; PLASMA DENSITY; SPATIAL RESOLUTION