Research Updates

July 2019

InGaP electron spectrometer for high temperature environments

In this work, a 200 mu m diameter InGaP (GaInP) p(+)-i-n(+) mesa photodiode was studied across the temperature range 100 degrees C to 20 degrees C for the development of a temperature-tolerant electron spectrometer. The depletion layer thickness of the InGaP device was 5 mu m. The performance of the InGaP detector was analysed under dark conditions and then under the illumination of a 183 MBq Ni-63 radioisotope beta particle source. The InGaP photodiode was connected to a custom-made low-noise charge-sensitive preamplifier to realise a particle counting electron spectrometer. Beta spectra were collected at temperatures up to 100 degrees C with the InGaP device reverse biased at 5V. The spectrum accumulated at 20 degrees C was compared with the spectrum predicted using Monte Carlo simulations; good agreement was found between the predicted and experimental spectra. The work is of importance for the development of electron spectrometers that can be used for planetary and space science missions to environments of high temperature or extreme radiation (e.g. Mercury, Jupiter’s moon Europa, near-Sun comets), as well as terrestrial applications.

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