Diagnostics for Tokamak Divertor Plasma
Research and Development of Advanced Diagnostics for Divertor Plasma in the KTM Tokamak
Tech Area / Field
- INS-DET/Detection Devices/Instrumentation
- FIR-INS/Nuclear Instrumentation/Fission Reactors
- FUS-PLA/Plasma Physics/Fusion
- INF-ELE/Microelectronics and Optoelectronics/Information and Communications
3 Approved without Funding
TRINITI, Russia, Moscow reg., Troitsk
- National Nuclear Center of the Republic of Kazakstan / Institute of Atomic Energy (2), Kazakstan, Kurchatov\nRussian Academy of Sciences / Physical Technical Institute, Russia, St Petersburg
- ENEA, Italy, Frascati
Project summaryThe project is focused on development of the advanced diagnostics for measurement of pertor plasma parameters on the KTM tokamak, in particular, for research of Lithium impurity transport in the pertor zone and in the scrape-off layer. Development and manufacture of three complementary diagnostic systems is supposed as a result of the project: an ultra-fast 2-D pinhole camera for a vacuum ultra-violet (VUV) range, high-resolution multichannel optical spectrometer and combined microwave diagnostics for measurement of parameters of plasma in the vicinity of the X-point.
The project will be carried out by efforts of three institutions: State research center of Russian Federation “Troitsk Institute for Innovation and Fusion Research” (TRINITI, Troitsk), Ioffe Physico-Technical Institute of Russian Academy of Science (Ioffe Institute, St.Petersburg), and Institute of Atomic Energy of National Nuclear Center of Kazakhstan Republic (IAE NNC, Kurchatov, RK). Researches will be carried out on the basis of results, obtained earlier by these institutions.
Specialists of TRINITI have significant experience in the development of plasma diagnostic systems for tokamak-reactors, in particular with use of VUV, visible and microwave detectors. TRINITI has T-11M tokamak – a plasma device with magnetic confinement for experimental modeling of the processes in fusion plasma, including those related to the impurity transport and it’s radiating characteristics in the VUV-range.
TRINITI succeeded in the development and use of multi-channel diagnostics of high-temperature plasma. Since 1996 within 10 years a number of systems have been created and installed to the following plasma devices: Angara - 5, tokamaks N-10, T-11M and Globus (Russia), DIII-D, NSTX (USA), JET (Great Britain), HL-1M (China), and KTM (Kazakhstan). Key participants of the project have an experience of working in the ISTC of projects ## 447, 2283, 2503.
Ioffe Institute is one of leading Russian research centers conducting R&D semiconductor structures with special properties. Researches of technology of silicon detectors have begun in 70-s' years of the last century and proceed up to present time. These researches, in particular, have been devoted to manufacturing of the silicon diode with the characteristic of "ideal" Shockley diode. Significant progress had been reached in development of original technology of silicon detectors (SPD photodiodes) both for 200-1100 nm spectral range, and for low-energy particles. Also, the pioneer works were done on development of detectors with ultimate noise performance at a level of fundamental restrictions. In cooperation with the foreign colleagues from Germany, a few SPD detectors were tested in wide VUV spectrum range. There is an experience of working in the ISTC project #2630.
Within the framework of given project, Ioffe Institute will produce linear and matrix arrays of detectors for VUV range for high vacuum applications. The proper technology and testing equipment are available. TRINITI will perform testing and final assembling of pinhole camera and total diagnostic system, including the vacuum equipment needed to install it to a tokamak port. Finally the diagnostic will be installed to the T-11M tokamak in TRINITI for investigation of impurity radiation profile evolution in various plasma discharge modes.
The institute of atomic energy IAE NNC RK has remarkable experience of development of the measurement instrumentation, software, and testing of various diagnostic systems in the projects of a nuclear safety, carried out on IAE experimental facilities together with Japan research centers. Two large-scale test benches had been developed within these projects for carrying out the experimental researches of uranium dioxide fusing in high-temperature furnaces. A number of control and measurements systems, and also diagnostics with application of optical, X-ray and other methods have been created for this purpose, including the software for data acquisition, storage and processing. The KTM tokamak complex is being built now in the IAE NNC RK in collaboration with Russian institutions, and some basic sub-systems including the physical diagnostics are developed by IAE specialists. Participants of the present project will participate in developing of measurements and interface units for electronic and vacuum sub-systems for the pertor plasma diagnostics, and also in their testing on the KTM tokamak together with TRINITI specialists.
Collaborators of the project will carry out an independent evaluation, and if necessary - additional researches and tests of the diagnostics developed in the project, and will make an estimation of results from the point of view of their applicability in various areas of a science and technical equipment.
Owing to the given project, "weapon" scientists and engineers will have an opportunity to be involved in research and development in peaceful scientific and technical area. The project will allow the Russian "weapon" experts to join closer the international scientific community.
Matrix array Silicon photodetectors (SPD) which will be developed in the given project could be applied to a broad area of metrological tasks in a wide spectral range from extreme ultraviolet up to visible light. Thus, the project concerns to the ISTC priority scientific and technical areas: the control of an environment, manufacture of energy and nuclear safety.
Within the framework of given project, Ioffe Institute will produce VUV detector linear and matrix arrays for high vacuum applications. The proper technology and testing equipment are available. TRINITI will carry out testing and final assembly of pinhole cameras, and total diagnostic system and IAE NNC will perform the final testing and installation at the KTM tokamak. In other words, manufacturing and researches will be carried out within the framework of a uniform research-and-production cycle, which in the methodical plan favorably distinguishes the given project.
Major project tasks to be solved:
Task 1. Development and manufacturing of ultra-fast two-dimensional pinhole camera on the basis of the hybrid matrix VUV detector.
Major feature of this task is to provide maximum dense and regular packing of hybrid 2x16 sub-modules into the matrix module with 16x16 format, and at the same time to preserve the minimum level of inter-channel photo-electric cross-talk, including in the high frequency range. In addition, the design should be made with materials and component, which are able to sustain a long-term (for a few days) gas desorption in high vacuum at temperature up to 150 C. All these demands require very careful design, stage-by-stage prototyping and testing of separate elements and the whole system.
Task 2. Development of high-resolution multi-channel spectrometer.
Eight-channel high-resolution visible range spectroscopic system will be developed for tangential observation of plasma X-point area of the KTM tokamak. Also the algorithm of processing and interpretation of the spectroscopic data will be developed and tested.
Task 3. Development of combined microwave X-point diagnostics.
Combined microwave diagnostics of plasma electron density profile evolution in the vicinity of the KTM plasma X-point will be developed, based on a combined measurements provided by the interferometer and pulse radar-refelectometer. Joint measurements with the help of two subsystems will provide the information on the X-point location and plasma electron density profile in the vicinity. The development and manufacture of a prototype diagnostic system consisting of a few number of channels, with subsequent installation on the KTM tokamak for testing and physical experiments is supposed within the framework of the project.
Task 4. Installation of the diagnostics on the T-11M and KTM tokamaks. Carrying out of starting tests, completion of a development, obtaining of experimental data in plasma discharges, research of behavior of impurity (Carbon, Lithium, etc.) at various modes of plasma discharge.
Basic complexity of the given task is the necessity of deep insertion of the pinhole camera into the vacuum port. Taking into account a parallel operating mode of the big number of analog channels, it is required about 50 flexible electric connections and corresponding vacuum elements, to provide their appropriate shielding and isolation from the tokamak vessel. Also, an opportunity of long-term vacuum baking of at the temperature up to 150 C for gas desorption of all internal surfaces is needed. However, an experience of developing of similar devices obtained earlier in TRINITI seems to be enough to believe in successful solution of this task.
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