High-count-rate proportional counter for soft x-ray position detection.

The design of a multiwire gas proportional counter for soft x-ray detection is described. Position information is obtained over a length of 110 mm from the signal induced in the cathode plane consisting of a delay line. A position resolution of better than 80 μm is demonstrated in tests performed with fluorescent x rays of well-defined energies in the range 1.6–6 keV. Count-rate capabilities reaching 1 MHz are demonstrated in crystal spectrometer measurements of the x-ray emission from tokamak plasmas. The use of this type of detector in other applications is also discussed, especially in view of the potential of measuring the xy position over areas up to 110×160 mm2. [ABSTRACT FROM AUTHOR]