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Soft X-Ray Tomography Imaging

报告人：霍昆成员：霍昆 时培运 王彦鹏

余鹏程 朱军峰

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Bremsstrahlung Radiation

• [Proper Te Distribution Assumption]

• ( Soft X-Ray(SXR) Imaging Reason 1: , power decreases exponentially;

Reason 2: , recombination line decreases as n;

I.H. Hutchinson, Principles of Plasma Diagnostics, Cambridge University Press, 2005.

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Application of SXR Imaging

𝐼 ∝ 𝑍𝑒𝑓𝑓 𝑛𝑒2𝑇𝑒

𝛾

Not proper to deduct absolute ;

Relative variations of the combination of plasma parameters Magnetic Surface

(Assumption!) MHD phenomenon

Magnetic Surface Evolution

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Optical Ray Consideration(1)

Internal machine components

Port access

Proximity of surroundings

p=1@𝑝=𝑟 𝑎=0.27𝑚

C. Janicki, R. Decoste, P. Noël, Review of Scientific Instruments ,63 (1992) 4410-4417.

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Optical Ray Consideration(2)

Etendue Area*:

Signal-to-Noise Ratio:

Maximum of

http://en.wikipedia.org/wiki/Etendue

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Design Result

Physics Objection Resolution:

Reconstruction 5 arrays*16 detectors/array (Poloidal resolution*Radial resolution)

Improved useful coverage* Asymmetrical arrangement

J.H. Williamson, D.E. Evans, 10 (1982) 82-93.

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Detector and Signal Processing

Surface Barrier Diode

Filter(Fixed): Be foil1.0~15KeV

LF~10KzHF~100kHz

Raw Signal~10-100nA

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Calibration

Besides, considering reconstruction process, one could tune detectors to satisfy

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Reconstruction--- Principle

•

where, , and is Chebyshev Polynomial.

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Reconstruction--- TruncationPoloidal: 5 arrays 10 s 10 harmonics M=4

Radial: Node spacing~2.5cm, a=27cm L~10

Consideration of numerical process:Akaike Information Criterion(AIC)

Where,

M=3,L=5~6

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Cautions Physics Assumption:

Principle:

Reconstruction:

Fluctuation is azimuthally symmetrical; Numerical Artifacts:

Different set of Different reconstruction;

Infinite expansion Finite series Truncation Error;

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Etendue

C. Janicki, Plasma Physics and Controlled Fusion, 35 (1993) 493-510.

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3-D Ray Representation

J. Kim, W. Choe, Review of Scientific Instruments, 75 (2004) 3974-3976.

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Bremsstrahlung Radiation