A pinhole camera with microchannel plates for hot electron spatial distribution measurement

A sensitive X-ray pinhole camera with microchannel plates (MCPs) has been constructed and successfully used to obtain X-ray images of hot electron distributions produced by electron cyclotron resonance heating in the thermal barrier region of the axisymmetrized tandem mirror GAMMA 10. Tomographic techniques have been applied to reconstruct a 2-dimensional X-ray intensity distribution. It is found that hot electrons are accumulated on the magnetic axis in a disc-like shape with a full width at half maximum (FWHM) diameter of about 25 cm. (author)