Large area position-sensitive X-ray detector for a Bragg crystal spectrometer

Abstract A large area position-sensitive X-ray detector was constructed for the Bragg crystal spectrometer on the Doublet III tokamak. The detector has good spatial resolution, high efficiency, and a high count rate capability. The average spatial resolution is 295 μm over the 20 × 6.6 cm 2 entrance window and 240 μm over the central 7 cm. With the detector pressurized with 70% Ar:30% CH 4 to 3.0 atm, an efficiency of 75% for 4.75 keV X-rays is obtained. This can be improved to 90% efficiency using a 70% Xe:30% CO 2 gas mixture. The detector count rate capability is > 100 kHz with negligible counting losses. The packaging is very compact for ease of shielding.