Active silicon x-ray for measuring electron temperature

Conference · Fri Jul 01 04:00:00 EDT 1994

OSTI ID:10176760

Snider, R T

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 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 squart 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 will be discussed along with comparisons to similar methods for measuring electron temperature and other applications of an active silicon x-ray filter.

• Research Organization: General Atomics, San Diego, CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC03-89ER51114
• OSTI ID: 10176760
• Report Number(s): GA-A--21694; CONF-940552--26; ON: DE94017521; BR: 35AT10020/35KC07000
• Country of Publication: United States
• Language: English

Related Subjects

440100
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700320
ELECTRON TEMPERATURE
PLASMA DIAGNOSTIC TECHNIQUES AND INSTRUMENTATION
PLASMA DIAGNOSTICS
RADIATION INSTRUMENTATION
SEMICONDUCTOR DIODES
SI SEMICONDUCTOR DETECTORS
TOKAMAK DEVICES
X-RAY DETECTION
X-RAY SPECTRA