Intensified CCD camera system for plasma diagnostics (abstract)

Abstract

It is possible to put together an intensified imaging system which has about the same sensitivity as photomultiplier tubes. Such a camera system, which utilizes a combination of image intensifiers and CCD image sensor, was constructed recently for the multipoint Thomson scattering diagnostic on Doublet III. In our case, the incoming image is first gated and amplified in the intensifier stages, then lens coupled to a CCD camera cooled to LN2 temperature. The camera contains a RCA back-illuminated CCD of 320×512 pixels, has a good quantum efficiency (≂85% at 550 nm), and has a noise level per pixel of about 60 electrons. The system is controlled through CAMAC with a photometric camera controller which allows a number of pictures to be taken and stored on the CCD chip for later readout. The multipicture capability is convenient for use with a multipulse Thomson scattering diagnostic to provide ne and Te profile measurements at several time points in a plasma shot. It is also conceivable that the camera system can be utilized to directly view the two-dimensional spatial distribution of plasma radiation at a particular energy in the range from near-infrared to soft x rays for information relating to plasma activities on flux surfaces.