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Title: Diamond neutral particle spectrometer for fusion reactor ITER

Abstract

A compact diamond neutral particle spectrometer with digital signal processing has been developed for fast charge-exchange atoms and neutrons measurements at ITER fusion reactor conditions. This spectrometer will play supplementary role for Neutral Particle Analyzer providing 10 ms time and 30 keV energy resolutions for fast particle spectra in non-tritium ITER phase. These data will also be implemented for independent studies of fast ions distribution function evolution in various plasma scenarios with the formation of a single fraction of high-energy ions. In tritium ITER phase the DNPS will measure 14 MeV neutrons spectra. The spectrometer with digital signal processing can operate at peak counting rates reaching a value of 10{sup 6} cps. Diamond neutral particle spectrometer is applicable to future fusion reactors due to its high radiation hardness, fast response and high energy resolution.

Authors:
; ; ;  [1]
  1. Institution PROJECT CENTER ITER, 1, Akademik Kurchatov Sq., Moscow (Russian Federation)
Publication Date:
OSTI Identifier:
22308280
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1612; Journal Issue: 1; Conference: International conference on fusion reactor diagnostics, Varenna (Italy), 9-13 Sep 2013; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ATOMS; CHARGE EXCHANGE; COUNTING RATES; DIAMONDS; DISTRIBUTION FUNCTIONS; ENERGY RESOLUTION; IONS; ITER TOKAMAK; MEV RANGE 10-100; NEUTRAL PARTICLE ANALYZERS; NEUTRAL PARTICLES; NEUTRON SPECTRA; NEUTRONS; PLASMA; PROCESSING; RADIATION HARDNESS; SIGNALS; TRITIUM

Citation Formats

Krasilnikov, V., Amosov, V., Kaschuck, Yu., and Skopintsev, D.. Diamond neutral particle spectrometer for fusion reactor ITER. United States: N. p., 2014. Web. doi:10.1063/1.4894041.
Krasilnikov, V., Amosov, V., Kaschuck, Yu., & Skopintsev, D.. Diamond neutral particle spectrometer for fusion reactor ITER. United States. doi:10.1063/1.4894041.
Krasilnikov, V., Amosov, V., Kaschuck, Yu., and Skopintsev, D.. Thu . "Diamond neutral particle spectrometer for fusion reactor ITER". United States. doi:10.1063/1.4894041.
@article{osti_22308280,
title = {Diamond neutral particle spectrometer for fusion reactor ITER},
author = {Krasilnikov, V. and Amosov, V. and Kaschuck, Yu. and Skopintsev, D.},
abstractNote = {A compact diamond neutral particle spectrometer with digital signal processing has been developed for fast charge-exchange atoms and neutrons measurements at ITER fusion reactor conditions. This spectrometer will play supplementary role for Neutral Particle Analyzer providing 10 ms time and 30 keV energy resolutions for fast particle spectra in non-tritium ITER phase. These data will also be implemented for independent studies of fast ions distribution function evolution in various plasma scenarios with the formation of a single fraction of high-energy ions. In tritium ITER phase the DNPS will measure 14 MeV neutrons spectra. The spectrometer with digital signal processing can operate at peak counting rates reaching a value of 10{sup 6} cps. Diamond neutral particle spectrometer is applicable to future fusion reactors due to its high radiation hardness, fast response and high energy resolution.},
doi = {10.1063/1.4894041},
journal = {AIP Conference Proceedings},
number = 1,
volume = 1612,
place = {United States},
year = {Thu Aug 21 00:00:00 EDT 2014},
month = {Thu Aug 21 00:00:00 EDT 2014}
}
  • In the development of magnetically confined fusion as an economically sustainable power source, International Tokamak Experimental Reactor (ITER) is currently under construction. Beyond ITER is the demonstration fusion reactor (DEMO) programme in which the physics and engineering aspects of a future fusion power plant will be demonstrated. DEMO will produce net electrical power. The DEMO programme will be outlined and the role of neutral beams for heating and current drive will be described. In particular, the importance of the efficiency of neutral beam systems in terms of injected neutral beam power compared to wallplug power will be discussed. Options formore » improving this efficiency including advanced neutralisers and energy recovery are discussed.« less
  • Coherent magnetohydrodynamic modes have been observed previously during neutral beam injection in the PDX tokamak (Phys. Rev. Lett. {bold 50}, 891 (1983)) and they have now been seen in the TFTR tokamak (Phys. Fluids {bold 26}, 2958 (1983)). Periodic bursts of oscillations were detected with several plasma diagnostics, and Fokker--Planck calculations show that the populations of trapped particles in both tokamaks are sufficient to account for fishbone destabilization if a resonant interaction, between the mode and the beam ions, is assumed. Estimates of mode parameters are in reasonable agreement with the experiments, and they indicate that the fishbone mode maymore » continue to affect the performance of intensely heated tokamaks.« less
  • Results of numerical simulation of signals from neutral particle analyzers under injection of the heating and diagnostic neutral beams in different operating modes of the ITER tokamak are presented. The distribution functions of fast ions in plasma are simulated, and the corresponding neutral particle fluxes escaping from the plasma along the line of sight of the analyzers are calculated. It is shown that the injection of heating deuterium (D{sup 0}) beams results in the appearance of an intense background signal hampering measurements of the ratio between the densities of deuterium and tritium fuel ions in plasma in the thermal energymore » range. The injection of a diagnostic hydrogen (H{sup 0}) beam does not affect measurements owing to the high mass resolution of the analyzers.« less
  • A central task for fusion plasma diagnostics is to measure the 2.5 and 14 MeV neutron emission rate in order to determine the fusion power. A new method for determining the neutron yield has been developed at JET. It makes use of the magnetic proton recoil neutron spectrometer and a neutron camera and provides the neutron yield with small systematic errors. At ITER a similar system could operate if a high-resolution, high-performance neutron spectrometer similar to the MPR was installed. In this paper, we present how such system could be implemented and how well it would perform under different assumptionmore » of plasma scenarios and diagnostic capabilities. It is found that the systematic uncertainty for using such a system as an absolute calibration reference is as low as 3% and hence it would be an excellent candidate for the calibration of neutron monitors such as fission chambers. It is also shown that the system could provide a 1 ms time resolved estimation of the neutron rate with a total uncertainty of 5%.« less
  • The international fusion experiment ITER requires for the plasma heating and current drive a neutral beam injection system based on negative hydrogen ion sources at 0.3 Pa. The ion source must deliver a current of 40 A D{sup -} for up to 1 h with an accelerated current density of 200 A/m{sup 2} and a ratio of coextracted electrons to ions below 1. The extraction area is 0.2 m{sup 2} from an aperture array with an envelope of 1.5x0.6 m{sup 2}. A high power rf-driven negative ion source has been successfully developed at the Max-Planck Institute for Plasma Physics (IPP)more » at three test facilities in parallel. Current densities of 330 and 230 A/m{sup 2} have been achieved for hydrogen and deuterium, respectively, at a pressure of 0.3 Pa and an electron/ion ratio below 1 for a small extraction area (0.007 m{sup 2}) and short pulses (<4 s). In the long pulse experiment, equipped with an extraction area of 0.02 m{sup 2}, the pulse length has been extended to 3600 s. A large rf source, with the width and half the height of the ITER source but without extraction system, is intended to demonstrate the size scaling and plasma homogeneity of rf ion sources. The source operates routinely now. First results on plasma homogeneity obtained from optical emission spectroscopy and Langmuir probes are very promising. Based on the success of the IPP development program, the high power rf-driven negative ion source has been chosen recently for the ITER beam systems in the ITER design review process.« less