Optimisation of design parameters for collimators and pin-holes of bolometer cameras

Fusion Engineering and Design

Penzel

Szabo-Balint

et al. 2019

Self Cite

The ITER bolometer diagnostic shall provide the measurement of the total radiation emitted from the plasma, a part of the overall energy balance. Up to 550 lines-of-sight (LOS) will be installed in ITER observing the whole plasma from many different angles to enable reliable measurements and tomographic reconstructions of the spatially resolved radiation profile. The performance of the diagnostic is intimately linked to the constraints imposed by the design requirements, the sensor and data acquisition design, as well as expected noise levels.The results presented contain the estimated signal intensities for the current design and integration of bolometer cameras in ITER, based on the simulated radiation profile for the ITER standard scenario (DT-plasma at 15 MA, 500 MW with low impurity content). The corresponding power deposited onto the absorber ranges between 0.5 µW and 2 mW. The expected noise levels derived mainly from lab measurements and compared to operating bolometer systems yield estimated values for ITER in the order of 1 µW, clearly indicating a need for optimizing the diagnostic.The optimization potential is discussed. Cameras for which the light yield could be increased are identified. Also, the potential for enhancing the sensitivity by using different absorber thicknesses is explored.

Section: Bolometer Locationsmentioning

confidence: 99%

Performance estimations for the ITER bolometer diagnostic

Fusion Engineering and Design

Penzel

Szabo-Balint

et al. 2019

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“…In order to determine the optimal camera geometry and e.g. questions regarding the design of multi-aperture collimators, an optimisation as described 4 is performed. All ITER in-vessel diagnostics must use Mineral Insulated Cables (MIC) for the electrical connection as they are the only cables qualified for the in-vessel nuclear and vacuum environment.…”

Section: System Level Design Of the Port Plug Cameras And Its Submentioning

confidence: 99%

System level design of the ITER bolometer port plug cameras

Penzel

Review of Scientific Instruments

Hermann

et al. 2018

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The ITER bolometer diagnostic is planned to have 550 lines of sight (LOS) distributed all over the vessel. 240 channels are provided by cameras mounted in two Upper Ports and in one Equatorial Port. This paper describes the current status of the system level design of the port cameras and the solutions proposed on how to implement all required camera components while meeting a multitude of competing requirements. Sensor holders, support structures and different apertures depending on the camera type (pinhole or collimator), cable connectors, ceramic track plates and many mineral insulated cables have to be integrated within a restricted space envelope to guarantee functionality. The design of the internal electrical interfaces and the external mechanical mountings will be described as well. Using the example of an Upper Port camera with 60 LOS, the assembly of the camera components is explained and two currently discussed architecture options for the remote handling maintenance scheme in the hot cell are compared.

“…The LOS can be defined either by collimators or by pinhole cameras. Methods to derive the main design parameters of these camera types are described in [4] in detail. The camera type can be cho-sen according to the available construction space and the resultingétendue.…”

Section: Overview Of the Iter Bolometer Diagnosticmentioning

confidence: 99%

“…The definition of the main parameters of the collimator (length, no. of sub-collimators, dimensions of pinholes) are calculated according to [4]. However, the thickness of apertures inside the collimator, their number and exact placement determines the efficiency of reducing stray light and reflections.…”

Section: Collimatorsmentioning

confidence: 99%

“…For port plug cameras scoping studies were made to determine the type and the main design parameters of the cameras. Using the LOS distribution as proposed during the conceptual design review, the required space envelopes have been defined based on [4] and in cooperation with the port integrator. In the equatorial port plug EPP01 there are three cameras: one pinhole camera in the diagnostic shield module (DSM) no.…”

Section: Port Plug Camerasmentioning

confidence: 99%

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Current status of the design of the ITER bolometer diagnostic

Fusion Engineering and Design

Gliss

Hermann

et al. 2017

Self Cite

The ITER bolometer diagnostic shall provide the measurement of the total radiation emitted from the plasma, a part of the overall energy balance. 550 lines-of-sight (LOS) will be installed in ITER observing the whole plasma from many different angles to enable reliable measurements and tomographic reconstructions of the spatially resolved radiation profile. The LOS are bundled in 71 individual cameras, which will be located behind blanket modules on the vacuum vessel wall, in five divertor cassettes, in two upper port plugs and in one equatorial port plug. For all major design issues solutions have been elaborated and will be presented. The design of collimators has been developed and tested on prototypes to provide an exact definition of the required viewing cones of about 1 • while reliably reducing reflections, stray light and microwave stray radiation. A 3D-shaped ceramic printed circuit board is proposed to hold the sensor, orient it as desired, and provide good thermal contact as well as the bridge for electrically connecting external signal cables to the meanders on the sensor. The design of the camera housing for vacuum vessel and divertor cameras has been optimised for improved management of the thermal heat flow, supported by tests defining material properties and verifying analysis. Additionally, methods have been developed to derive the main design parameters of cameras and decide if pinhole or collimator type is more advantageous. Recently, the system-level design phase started and uses the achieved results to define interfaces and designs for the specific locations in ITER, with a focus on the vacuum-vessel cameras to finalise the interface with blanket modules.