Ge pixel array detector for high throughput x-ray absorption spectroscopy: performance and unconventional applications

For high throughput and energy-resolution fluorescence x-ray absorption spectroscopy (XAS), a novel Ge pixel array detector (PAD) with 100 segments has been developed. Two sets of PAD having different thickness values, i.e., 10 mm (no 1) and 7.5 mm (no 2), were constructed and installed at Spring-8 (BL10XU) and Photon Factory (BL13B). Using a monolithic approach, a nearly perfect packing fraction (>88%) and commission rate (99%) were achieved, resulting in a significant improvement over a previous Ge multi-element detector. In the present PAD design, each segment is square-shaped having an active area of 22 mm². The average energy resolution at 5.9 keV was 220 eV (6 μs shaping time) and 240 eV (0.5 μs) in a high throughput mode. High efficiency x-ray detection over a wide energy range (5–60 keV) was confirmed. The present electronics-limited throughput maximum is 100 kcps per channel or 10 MHz in total. We will describe unconventional applications in fluorescence XAS demonstrating the capability of PAD. The recent in-situ XAS study under laser light required a small amount of specimen less than 10^-3 g.