JET soft x-ray diode array diagnostic

Journal Article · Fri Aug 01 00:00:00 EDT 1986 · Rev. Sci. Instrum.; (United States)

DOI:https://doi.org/10.1063/1.1139200· OSTI ID:5642017

Edwards, A W; Fahrbach, H; Gill, R D; Granetz, R; Oord, E; Schramm, G; Tsuji, S; Weller, A; Zasche, D

The arrays of silicon diodes recently installed on the Joint European Torus (JET) measure the plasma soft x-ray emission with high temporal and spatial resolution, allowing magnetohydrodynamic (MHD) effects to be investigated. The diagnostic consists of two ''pinhole'' cameras which view the same poloidal cross section in orthogonal directions. A data-acquisition system based upon three cascaded digital filters can convert the 200-kHz detector signal analog-to-digital converter (ADC) output to lower sampling rates of 10, 1, and 0.1 kHz. Initially, studies have concentrated on the sawtooth collapse. By means of a trigger system data on the sawtooth crash have regularly been recorded at a sampling frequency of 200 kHz. Using tomographic reconstruction techniques, the soft x-ray emissivity cross section during the crash has been reconstructed. First results during ion cyclotron radio frequency (ICRF) heating show no precursor activity prior to the sawtooth collapse, while during the crash, the hot central plasma is displaced off axis by about 30 cm on a time scale of 50--200 ..mu..s, after which a hollow soft x-ray profile forms.

• Research Organization: JET Joint Undertaking, Abingdon, Oxon, United Kingdom
• OSTI ID: 5642017
• Journal Information: Rev. Sci. Instrum.; (United States), Vol. 57:8, Issue 8
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
JET TOKAMAK
DATA ACQUISITION SYSTEMS
PLASMA DIAGNOSTICS
SILICON DIODES
SOFT X RADIATION
RESOLUTION
X-RAY DETECTION
CONFIGURATION
FLUCTUATIONS
ICR HEATING
DETECTION
ELECTROMAGNETIC RADIATION
HEATING
HIGH-FREQUENCY HEATING
IONIZING RADIATIONS
PLASMA HEATING
RADIATION DETECTION
RADIATIONS
SEMICONDUCTOR DEVICES
SEMICONDUCTOR DIODES
THERMONUCLEAR REACTORS
TOKAMAK TYPE REACTORS
VARIATIONS
X RADIATION
700102* - Fusion Energy- Plasma Research- Diagnostics
440101 - Radiation Instrumentation- General Detectors or Monitors & Radiometric Instruments