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3. Optical configurations for the core CXRS diagnostics for ITER

Author

Klinkhamer, J.F.F. and Moddemeijer, K.

Subjects
OPT - Optics, TS - Technical Sciences, CXRS diagnostics, Port plugs, Optical properties, Physics, Opto-mechanical design, Optical design, Mirror lifetime, First mirror, Port plug, Core CXRS, Manufacturability, Degradation, Mirrors, Physics & Electronics, ITER, Optical systems, Off-axis, Optical configurations, Optics design, Imaging components
Abstract

For the optical system of the core CXRS port plug several designs were developed in the last years. A survey is given of the three most relevant designs. The first design is based on an off-axis ellipsoid mirror as main imaging component. This design has been the basis of opto-mechanical design as described in previous publications [1]. This design is presented and assessed with regard to the optical properties, the sensitivity to first mirror degradation, the possibility to include a tube to allow replacement of the first mirror (as a possible mitigation of the first mirror degradation) and the manufacturability. Two alternatives are presented that alleviate the issues connected to the optical design. These alternatives may improve both lifetime and manufacturability of the core CXRS port plug. © 2011 Published by Elsevier B.V.

Published
2011

4. The CXRS diagnostic for ITER and the CXRS-pilot experiment on TEXTOR

Author

Jaspers, R.J.E., Hellermann, M.G. von, Delabie, E., Boom, J.E., Donné, A.J.H., Biel, W., Hawkes, N.C., Neubauer, O., Di Maio, M., Sadakov, S., Klinkhamer, J.F.F., Snijders, B., Hogenbirk, A., and TNO Industrie en Techniek

Subjects
ITER, Beam Emission, TEXTOR, Charge Exchange Recombination Spectroscopy
Abstract

Charge eXchange Recombination Spectroscopy (CXRS) will play a crucial role in the diagnosing of burning plasmas: items like helium ash, transport barriers, impurity content or fuel ratio can all be assessed with CXRS. In fact this is the only direct method to obtain information about the light impurity ions, such as temperature, concentrations and rotation, in the core of the plasma. Two of such systems are foreseen at ITER, one in the upper port plug and one on the equatorial level, both viewing the 100 keV diagnostic H-beam. Challenges for this diagnostic development project are: constructing a mirror close to the plasma able to keep its reflectivity under the extreme bombardment by neutrons, erosion by fast neutrals and deposition of sputtered material, design of an optical labyrinth with well enough neutron shielding, developing spectrometers with a throughput about a factor 100 larger than on present day devices, with a similar or better dispersion, calibration and alignment techniques and last but not least, finding ways to obtain the physics relevant information from the measured complicated spectra in real time. With all these issues in mind, an ITER-CXRS pilot experiment has been developed and became operational on the TEXTOR tokamak, to address some of the above aspects. The results of this show the feasibility and the sensitivity of the ITER system: the simulation code for ITER signal levels could be verified, the sensitivity to the current profile has been tested, the beam emission has been compared to beam attenuation calculations and used to obtain absolute impurity concentrations and a high throughput spectrometer became operational.

Published
2008

5. Dealing with friction in a reusable 6 degrees of freedom adjustment mechanism with sliding contacts

Author

Klinkhamer, J.F.F. and Technisch Physische Dienst TNO - TH

Subjects
Kinematics, Friction, Sensors, Wafer, Optics, Opto-mechanics, Matrix algebra, Degrees of freedom (mechanics), Degrees of freedom, Adjustment procedure, Calibration, Electronics, Lighting
Abstract

Although the possibility of a 6 degrees of freedom adjustment based on a single body pulled onto on six adjustable supports follows directly from the kinematic theory, such mechanisms are seldom used in actual products. Two major drawbacks for the use of this solution are: Due to the sliding contact between the body and the supports, friction will occur and may inhibit movement. Coupling between the adjusted axes cannot be avoided, this may interfere with the necessity of an adjustment procedure with a limited number of iterations This paper presents a matrix calculation method that offers a prediction whether the body will move as required, depending on the position of the supports and on the magnitude of the friction. This method enables to check the functionality of a design. This method has been used in the design of several adjustment mechanisms consisting of a body pulled onto six supports. The matrix calculation method also allows predicting the movement of the adjusted body due to adjustment of the separate supports. Using this it is relatively simple to simulate the movements that an operator will observe, and in this way check whether an operator is capable to handle the couplings present in the adjustment. Using the simulation the adjustment procedure can be optimized.

Published
2003

6. Optimization of the availability of the core CXRS diagnostics for ITER

Author

Klinkhamer, J.F.F., Krimmer, A., Biel, W., Hawkes, N., Kiss, G., Koning, J., Krasikov, Y., Neubauer, O., Snijders, B., Klinkhamer, J.F.F., Krimmer, A., Biel, W., Hawkes, N., Kiss, G., Koning, J., Krasikov, Y., Neubauer, O., and Snijders, B.

Abstract

New optical configurations for the ITER core CXRS system offer the possibility of longer ducts between the first mirror and the plasma. This has led to a renewed optimization of the availability, using a simple model of the degradation of the first mirror that starts with the conditions of (a) the required measurement performance and (b) the geometry of the port plug. It is found that for a fully passive system the design should strive for the longest duct length possible. Given known data, this will result in a diagnostic lifetime still substantially shorter than ITER lifetime. When an option of cleaning the first mirror is introduced (assuming this is a feasible option) the optimum is less straightforward, because the lifetime of the second mirror then also becomes important. The optimum then depends on the ratio between the cleaning interval and the ITER lifetime. Options are presented for various sets of assumptions. Finally practical limitations of supporting subsystems (cleaning system, shutter, calibration system) may influence the final design. Examples of such limitations with their impact are presented. © 2011 Published by Elsevier B.V.

Published
2011

7. Alternative system design concepts for the ITER core CXRS upper port plug front end

Author

Krimmer, A., Klinkhamer, J.F.F., Biel, W., Hawkes, N., Kiss, G., Koning, J.F., Krasikov, Y., Neubauer, O., Krimmer, A., Klinkhamer, J.F.F., Biel, W., Hawkes, N., Kiss, G., Koning, J.F., Krasikov, Y., and Neubauer, O.

Abstract

The upper port #3 in ITER will be used by the core Charge Exchange Recombination Spectroscopy (core CXRS) to channel out light from the inside of the vacuum vessel. Recent research about the lifetime of the first two mirrors and changes in the upper port plug geometry initiated further investigations into possible alternative system design concepts. Two new variants of the optical system were chosen for further investigation. The different sub-systems of core CXRS such as optical system, retractable tube and shutter are introduced together with their impact on the system design and their interactions. Space constraints originating from the envelope of the UPP and requirements emerging from the ITER environment such as remote handling and other maintenance considerations are also included in the investigation. Alternative system concepts taking the constraints into account are presented and discussed. Implications for further design work on the subsystems are derived from the results. © 2011 Forschungszentrum Jülich, Association EURATOM-FZL. Published by Elsevier B.V. All rights reserved.

Published
2011

8. Active beam spectroscopy for ITER

Author

Hellermann, M.G. von, Barnsley, R., Biel, W., Delabie, E., Hawkes, N., Jaspers, R., Johnson, D., Klinkhamer, J.F.F., Lischtschenko, O., Marchuk, O., Schunke, B., Singh, M.J., Snijders, B., Summers, H.P., Thomas, D., Tugarinov, S., Vasu, P., Hellermann, M.G. von, Barnsley, R., Biel, W., Delabie, E., Hawkes, N., Jaspers, R., Johnson, D., Klinkhamer, J.F.F., Lischtschenko, O., Marchuk, O., Schunke, B., Singh, M.J., Snijders, B., Summers, H.P., Thomas, D., Tugarinov, S., and Vasu, P.

Abstract

Since the first feasibility studies of active beam spectroscopy on ITER in 1995 the proposed diagnostic has developed into a well advanced and mature system. Substantial progress has been achieved on the physics side including comprehensive performance studies based on an advanced predictive code, which simulates active and passive features of the expected spectral ranges. The simulation has enabled detailed specifications for an optimized instrumentation and has helped to specify suitable diagnostic neutral beam parameters. Four ITER partners share presently the task of developing a suite of ITER active beam diagnostics, which make use of the two 0.5 MeV/amu 18 MW heating neutral beams and a dedicated 0.1 MeV/amu, 3.6 MW diagnostic neutral beam. The IN ITER team is responsible for the DNB development and also for beam physics related aspects of the diagnostic. The RF will be responsible for edge CXRS system covering the outer region of the plasma (1>r/a>0.4) using an equatorial observation port, and the EU will develop the core CXRS system for the very core (0

Published
2010

9. Conceptual design of the ITER upper port plug for charge exchange diagnostic

Author

Sadakov, S., Baross, T., Biel, W., Borsuk, V., Hawkes, N., Hellermann, M. von, Gille, P., Kiss, G., Koning, J., Knaup, M., Klinkhamer, J.F.F., Krasikov, Yu., Litnovsky, A., Neubauer, O., Panin, A., Sadakov, S., Baross, T., Biel, W., Borsuk, V., Hawkes, N., Hellermann, M. von, Gille, P., Kiss, G., Koning, J., Knaup, M., Klinkhamer, J.F.F., Krasikov, Yu., Litnovsky, A., Neubauer, O., and Panin, A.

Abstract

A plug for the ITER core charge exchange recombination spectroscopy (core CXRS) is located in the upper port 3. It transfers the light emitted by interaction of plasma ions with the diagnostic neutral beam (DNB). The plug consists of a main shell, a shielding cassette and a retractable tube. The tube carries the first mirror (M1) with a shutter and allows multiple replacements of M1. A large uncertainty in the M1 lifetime has initiated a new design option with M1 located as far as possible from the first wall. A fast shutter has been proposed to enhance M1 protection. It operates consistently with a pulsed DNB and uses elastic bearings. Three-point attachment scheme of blanket shield modules (BSMs) has been suggested. It is capable to react electromagnetic loads caused by eddy- and halo-currents for any BSM option with a good design margin. The concern has been raised with regards to the forces caused by halo current and applied to the entire plug. Possible solutions are either to shunt and support the plug to the port in the frontal part, or re-attach all BSM in this belt from the plugs to the vacuum vessel. © 2009 Elsevier B.V. All rights reserved.

Published
2009

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