High temperature X-ray and γ-ray spectroscopy with a diamond detector

A single crystal chemical vapour deposition diamond detector was electrically characterised and then investigated as a spectroscopic photon counting X-ray and γ-ray detector across the temperature range, T, −20 °C ≤ T ≤ 100 °C. The detector was connected to a custom-built charge-sensitive preamplifier of low electronic noise and illuminated in turn by ⁵⁵Fe radioisotope X-ray and ¹⁰⁹Cd radioisotope X-ray and γ-ray sources. In combination, the radiation sources provided characteristic soft (e.g. 5.9 keV) and hard (e.g. 22.16 keV) X-rays and 88.03 keV γ-ray emissions. The Mn Kα (5.9 keV) and Kβ (6.49 keV) X-ray emissions from the ⁵⁵Fe radioisotope X-ray source were detected (and separated from the zero energy noise peak) at temperatures of −20 °C ≤ T ≤ 60 °C; the Ag Kα (22.16 and 21.99 keV) and Kβ (24.94, 24.99, and 25.46 keV) X-ray emissions and 88.03 keV γ-ray emissions were detectable across the entire temperature range investigated (−20 °C ≤ T ≤ 100 °C). The detector and the preamplifier were operated without cooling across the entire temperature range. The energy resolution (full width at half maximum) at 22.16 keV (Ag Kα₁) was 4.57 keV ± 0.26 keV at 100 °C and 2.70 keV ± 0.18 keV at −20 °C. Noise analysis indicated that the combination of dielectric noise and any incomplete charge collection noise present dominated the other noise components at 5.9 keV. When the detector was illuminated with the ¹⁰⁹Cd radioisotope X-ray and γ-ray source, a high count rate introduced parasitic effects (possibly baseline shift) which reduced the optimum shaping time of the spectrometer.