The Hard X-ray Camera on the PBX-M tokamak (invited) (abstract)

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

DOI:https://doi.org/10.1063/1.1146291· OSTI ID:6691024

Goeler, S v; Jones, S; Kaita, R; Bell, R; Bernabei, S; Davis, W; Gettelfinger, G; Ignat, D; Roney, P; Petravich, G ^[1]

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1. Plasma Physics Laboratory, Princeton University, Box 451, Princeton, New Jersey 08543 (United States)

The modification and control of the plasma current profile by lower hybrid current drive is considered one of the most promising avenues to control MHD instabilities and improve the high beta performance of tokamaks. The Hard X-ray Camera on PBX-M records images of the bremsstrahlung emitted by suprathermal electrons that carry part of the plasma current during lower hybrid current drive. The Hard X-ray Camera is a pinhole camera that uses a 9 in. diam x-ray intensifier as detector. It provides a tangential view of the tokamak plasma and delivers 64 images with 128[times]128 pixels per plasma shot. The spatial resolution in the plasma is approximately 2 cm, and the time resolution 3 ms. The camera is sensitive to x rays between 30 and 200 keV. The photon energy (and the energy of the suprathermal electrons) is measured with an absorber foil method. Modeling of the x-ray emission has reproduced the experimental images with a better than 10% accuracy. In addition, two inversion techniques have been developed: one of these can be performed on line between shots. Illustrative examples of important applications of hard x-ray imaging will be given. The hard x-ray images provide information on the radial location of the absorption of the lower hybrid waves, on the velocity distribution of the suprathermal electrons, on the diffusion of superthermal electrons, and on anomalous hot electron transport induced by MHD instabilities.

• DOE Contract Number: AC02-76CH03073
• OSTI ID: 6691024
• 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-)
BREMSSTRAHLUNG
CAMERAS
CLOSED PLASMA DEVICES
ELECTROMAGNETIC RADIATION
HARD X RADIATION
HEATING
HIGH-FREQUENCY HEATING
IMAGE PROCESSING
INSTABILITY
IONIZING RADIATIONS
LOWER HYBRID HEATING
PBX DEVICES
PLASMA DIAGNOSTICS
PLASMA HEATING
PLASMA INSTABILITY
PROCESSING
RADIATIONS
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
X RADIATION