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Title: Design, installation, commissioning and operation of a beamlet monitor in the negative ion beam test stand at NIFS

In the framework of the accompanying activity for the development of the two neutral beam injectors for the ITER fusion experiment, an instrumented beam calorimeter is being designed at Consorzio RFX, to be used in the SPIDER test facility (particle energy 100keV; beam current 50A), with the aim of testing beam characteristics and to verify the source proper operation. The main components of the instrumented calorimeter are one-directional carbon-fibre-carbon composite tiles. Some prototype tiles have been used as a small-scale version of the entire calorimeter in the test stand of the neutral beam injectors of the LHD experiment, with the aim of characterising the beam features in various operating conditions. The extraction system of the NIFS test stand source was modified, by applying a mask to the first gridded electrode, in order to isolate only a subset of the beamlets, arranged in two 3×5 matrices, resembling the beamlet groups of the ITER beam sources. The present contribution gives a description of the design of the diagnostic system, including the numerical simulations of the expected thermal pattern. Moreover the dedicated thermocouple measurement system is presented. The beamlet monitor was successfully used for a full experimental campaign, during which the main parametersmore » of the source, mainly the arc power and the grid voltages, were varied. This contribution describes the methods of fitting and data analysis applied to the infrared images of the camera to recover the beamlet optics characteristics, in order to quantify the response of the system to different operational conditions. Some results concerning the beamlet features are presented as a function of the source parameters.« less
Authors:
; ; ; ; ; ; ; ; ; ; ; ;  [1] ;  [1] ;  [2] ; ; ; ; ;  [3] more »;  [4] « less
  1. Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA) (Italy)
  2. (PD) Italy (Italy)
  3. National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292 (Japan)
  4. Istituto di Fisica del Plasma (IFP-CNR) – Via Cozzi 53, 20125, Milano (Italy)
Publication Date:
OSTI Identifier:
22391454
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1655; Journal Issue: 1; Conference: NIBS 2014: 4. International Symposium on Negative Ions, Beams and Sources, Garching (Germany), 6-10 Oct 2014; Other Information: (c) 2015 U.S. Government; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ATOMIC BEAMS; BEAM CURRENTS; BEAM EXTRACTION; BEAM INJECTION HEATING; CALORIMETERS; CARBON FIBERS; COMMISSIONING; COMPUTERIZED SIMULATION; DATA ANALYSIS; DESIGN; ELECTRIC POTENTIAL; GRIDS; HYDROGEN IONS 1 MINUS; ITER TOKAMAK; LHD DEVICE; MONITORS; PLASMA DIAGNOSTICS; TEST FACILITIES; THERMOCOUPLES; US NATIONAL IGNITION FACILITY