Active silicon x-ray filter for measuring electron temperature

Journal Article · Sun Jan 01 04:00:00 EST 1995 · Review of Scientific Instruments; (United States)

DOI:https://doi.org/10.1063/1.1146347· OSTI ID:6700606

Snider, R T ^[1]

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1. General Atomics, P.O. Box 85608, San Diego, California 92186-9784 (United States)

Silicon diodes are commonly used for x-ray measurements in the soft-x-ray region between a few hundred eV and 20 keV. Recent work by Cho [ital et] [ital al]. [J. Appl. Phys. [bold 72], 8 (1992)] has shown that the charge collecting region in an underbiased silicon detector is the depletion depth plus some contribution from a region near the depleted region due to charge diffusion. The depletion depth can be fully characterized as a function of the applied bias voltage and is roughly proportional to the square root of the bias voltage. We propose a technique to exploit this effect to use the silicon within the detector as an actively controlled x-ray filter. With reasonable silicon manufacturing methods, a silicon diode detector can be constructed in which the sensitivity of the collected charge to the impinging photon energy spectrum can be changed dynamically in the visible to above the 20-keV range. This type of detector could be used to measure the electron temperature in, for example, a tokamak plasma by sweeping the applied bias voltage during a plasma discharge. The detector samples different parts of the energy spectrum during the bias sweep, and the data collected contains enough information to determine the electron temperature. Benefits and limitations of this technique are discussed along with comparisons to similar methods for measuring electron temperature and other applications of an active silicon x-ray filter.

• DOE Contract Number: AC03-89ER51114
• OSTI ID: 6700606
• Journal Information: Review of Scientific Instruments; (United States), Journal Name: Review of Scientific Instruments; (United States) Vol. 66:1; ISSN 0034-6748; ISSN RSINAK
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700320* -- Plasma Diagnostic Techniques & Instrumentation-- (1992-)
CLOSED PLASMA DEVICES
DETECTION
ELECTRON TEMPERATURE
FILTERS
PLASMA DIAGNOSTICS
RADIATION DETECTION
SEMICONDUCTOR DEVICES
SEMICONDUCTOR DIODES
SENSITIVITY
SILICON DIODES
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
X-RAY DETECTION