Research Updates

August 2019

High temperature Alinp X-ray spectrometers

Two custom-made Al0.52In0.48P p(+)-i-n(+) mesa photodiodes with different diameters (217 mu m +/- 15 mu m and 409 mu m +/- 28 mu m) and i layer thicknesses of 6 mu m have been electrically characterised over the temperature range 0 degrees C to 100 degrees C. Each photodiode was then investigated as a high-temperature-tolerant photon counting X-ray detector by connecting it to a custom-made low-noise charge-sensitive preamplifier and illuminating it with an Fe-55 radioisotope X-ray source (Mn K alpha = 5.9 keV; Mn K beta = 6.49 keV). At 100 degrees C, the best energy resolutions (full width at half maximum at 5.9 keV) achieved using the 217 mu m +/- 15 mu m diameter photodiode and the 409 mu m +/- 28 mu m diameter photodiode were 1.31 keV +/- 0.04 keV and 1.64 keV +/- 0.08 keV, respectively. Noise analysis of the system is presented. The dielectric dissipation factor of Al0.52In0.48P was estimated as a function of temperature, up to 100 degrees C. The results show the performance of the thickest Al0.52In0.48P X-ray detectors so far reported at high temperature. The work has relevance for the development of novel space science instrumentation for use in hot space environments and extreme terrestrial applications.

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