Electron spectroscopy with a diamond detector

An electronic grade single crystal chemical vapour deposition diamond was investigated as a prototype high temperature spectroscopic electron (beta- particle) detector for future space science instruments. The diamond detector was coupled to a custom-built charge-sensitive preamplifier of low noise. A 63Ni radioisotope source (endpoint energy 66 keV) was used to provide a spectrum of beta- particles incident on the detector. The operating temperature of the detector/preamplifier assembly was controlled to allow its performance to be investigated between +100 degrees C and -20 degrees C, in 20 degrees C steps. Monte Carlo modelling was used to: a) calculate the beta- particle spectrum incident on the detector; b) calculate the fraction of beta- particle energy deposited into the detector; and c) predict the beta- particle spectrum accumulated by the instrument. Comparison between the model and experimental data suggested that there was a 4.5 mu m thick recombination region at the front of the detector. The spectrometer was demonstrated to be fully operable at temperatures, T, -20 degrees C < T 80 <degrees>C; the results suggested that some form of polarisation phenomenon occurred in the detector at 80 degrees C. This article presents the first report of an energy calibrated (< 50 keV) spectroscopic beta- particle diamond detector.